Abstract:

Inclination of an image display unit is prevented at the time of using a
wearable display unit in which the image display unit can move between a
projection position where the image display unit comes in front of a
user's eye and a retracted position where the image display unit has been
retracted from the front of the user's eye. A display support member 27
is prevented from rotating in relation to a display support member
housing part 31 in a direction included in a plane perpendicular to the
longitudinal direction of the display support member 27, even in a state
that the display support member can move. To that end, grooves 28a, 28b
extending in the longitudinal direction are formed in the display support
member 27, while guide rollers 34a, 34a in contact with these grooves are
provided within the display support member housing part 31.

Claims:

1. A wearable display system for displaying an image in front of an eye of
a user, comprising:a head-mounting member configured to be mounted on the
head of the user, the head-mounting member comprising a speaker and a
headphone arm connected to the speaker; anda wearable display unit,
comprising(i) an image-display unit having a screen configured to display
the image,(ii) a holder connected to the image-display unit,(iii) an
attachment that affixes the holder to the head-mounting member mounted to
the head of the user, and(iv) a joint that affixes the holder to the
attachment such that the holder is swingable in multiple directions
relative to the attachment, each of the multiple directions being a
respective direction of swing around a respective one of a plurality of
virtual axes that are different from one another,wherein, with respect to
the joint, a torque for swinging around at least one of the virtual axes
is different from a torque required for swinging around another of the
virtual axes, andwherein one of the virtual axes is a virtual rotation
axis about which the image-display unit, fixed to the holder, swings in a
plane including a vertical direction, in a state in which the
head-mounting member has been mounted to the head and the attachment is
coupled to the holder, and a torque required for swinging the
image-display unit around the subject virtual rotation axis is larger
than a torque required for swinging around another virtual axis.

2. The wearable display system of claim 1, wherein the joint comprises:a
first joint portion configured to hold the holder on the attachment such
that the holder can swing relative to the attachment around a first
virtual axis among the multiple virtual axes; anda second joint portion
configured to hold the holder on the attachment such that the holder can
swing relative to the attachment around a second virtual axis that is
perpendicular to the first virtual axis.

3. The wearable display system of claim 1, wherein:the joint comprises a
first joint portion and a second joint portion;the first joint portion
comprises a respective base-side member configured to be fixed to or
formed integrally with the attachment and a respective swing-side member
that is held to the base-side member such that the swing-side member can
rotate relative to the base-side member around the first virtual axis;
andthe second joint portion comprises a respective swing-side member
configured to be fixed to or formed integrally with the holder, and a
respective base-side member that is held to the swing-side member such
that the base-side member can rotate relative to the swing-side member
around the second virtual axis, the second joint portion being fixed to
the swing member of the first joint portion.

[0002]The present disclosure relates to a wearable display unit provided
with an image display unit for displaying an image in front of an eye of
a user and the image display unit can be arranged near a user's eye,
headphones attached to the wearable display unit, and a system provided
with these components.

[0003]As a device for displaying an image in front of an eye of a user,
there is a device called a wearable display unit or a head-mounted
display.

[0004]For example, the below-mentioned Non-patent Document 1 shows a
conventional device of such a type.

[0005]A wearable display unit described in Non-patent Document 1
comprises: an image display unit; a round-bar-shaped display support
member whose end fixes the image display unit; a display support member
holding part that supports the display support member slidably; and a
head mounting belt to which the display support member holding part is
attached. The display support member holding part comprises: a display
support member housing that houses the display support member; and a
restricting screw for restricting the display support member such that
the display support member can not move relatively to the display support
member housing. The display support member housing is formed with a
display support member through hole for inserting the display support
member and a threaded hole extending in the direction intersecting the
display support member through hole. The restricting screw is screwed
into the threaded hole and presses the display support member in the
display support member housing to restrict the display support member
such that the display support member can not move.

[0006]To use this wearable display unit, first the head mounting belt is
put on the head of a user. Then, the restricting screw is loosened to
pull out the display support member from the display support member
housing such that the image display unit is led to the front of a user's
eye. Then, the display support member is rotated slightly in relation to
the display support member housing around the longitudinal axis of the
display support member, to adjust the inclination of the image display
unit. Thereafter, the restricting screw is screwed into the display
support member housing to restrict the display support member such that
the display support member can neither move nor rotate.

[0008]A wearable display unit described in Patent Document 1 has a head
mounting belt and a display device. Mechanical structures for fixing the
display device unit are provided to the head mounting belt in the
neighborhoods of the right and left eyes, respectively. Thus, since this
wearable display unit is provided with the mechanical structures for
fixing the display device unit at the portions of the head mounting belt
in the neighborhoods of the right and left eyes respectively, it is
possible to place the display device unit both in the neighborhood of the
right eye and in the neighborhood of the left eye.

[0009]Patent Document 2 describes a wearable display unit whose image
display unit is provided with an anti-swing member that can be in contact
with a nose of a user to avoid effect of unintended movement of the image
display unit owing to a motion of the user.

[0010]A wearable display unit described in Patent Document 3 comprises: an
image display unit for displaying an image in front of a user's eye; a
head mounting member to be mounted on the head of the user; a display
support member that supports the image display unit; and a coupling
member for coupling the display support member to the head mounting
member. This wearable display unit has a spherical seat at a portion of
connection between the display support member and the coupling member so
that the image display unit fixed to the end of the display support
member can swing in various directions together with the display support
member.

[0015]According to the technique described in Non-patent Document 1, the
center of gravity of the image display unit does not exist on the axis of
the display support member. Thus, when the wearable display unit is used
in a state that the image display unit is positioned in front of a user,
sometimes the weight of the image display unit generates force causing
the display support member to rotate on its longitudinal axis and, as a
result, the image display unit to incline. In particular, when the head
of the user using the wearable display unit moves rapidly, the image
display unit frequently inclines downward even if the restricting screw
has been screwed tightly to some degree.

[0016]The present invention has been made considering these conventional
problems. An object of the present invention is to provide a wearable
display unit that can prevent downward inclination of an image display
unit at the time of using, headphones that can be fixed to this wearable
display unit, and a system provided with these.

[0017]To solve the above problems, one aspect of the invention provides a
wearable display unit having an image display unit for displaying an
image in front of an eye of a user and the image display unit of which
can be arranged near a user's eye. An embodiment of the unit comprises a
display support member that has a bar shape and is fixed to the image
display unit. The unit also comprises a display support member holding
part that holds the display support member movably between a projecting
position where the image display unit can be positioned in front of the
eye of the user and a retracted position where the image display unit has
been retracted from the front of the eye of the user. The unit also
comprises an anti-rotation means that prevents rotation of the display
support member in relation to the display support member holding part in
a neighborhood of, and including at least, the projecting position
between the projecting position and the retracted position, with respect
to rotation in a direction within a plane nearly perpendicular to a
longitudinal direction of the display support member, even when the
display support member is in a movable state.

[0018]In the wearable display unit, the anti-rotation means can comprise
an anti-rotation-shape part formed, at least in a part of the display
support member, to have an outer peripheral shape of a cross section
having parts whose distances from a center of gravity in the cross
section are different from each other. The cross section can be
perpendicular to the longitudinal direction of the display support
member. The anti-rotation means also can include an abutting part that is
a part of the display support member holding part and cannot be rotated
in a sense of the rotation, with the abutting part abutting on the
anti-rotation-shape part of the display support member at least in the
neighborhood of the projecting position.

[0019]In another embodiment the anti-rotation means comprises an
anti-rotation-shape part formed, at least in a part of the display
support member, to have an outer peripheral shape of a cross section
different from a circle, with the cross section being perpendicular to
the longitudinal direction of the display support member. The
anti-rotation means also comprises an abutting part that is a part of the
display support member holding part and cannot be rotated in a sense of
the rotation, with the abutting part abutting on the anti-rotation-shape
part of the display support member at least in the neighborhood of the
projecting position.

[0020]The outer peripheral shape of the cross section of the display
support member can be different between on a tip end side to which the
image display unit is fixed and on a base end side opposite to the tip
end side. The base end portion of the display support member can form the
anti-rotation-shape part.

[0021]The outer peripheral shape of the cross section on the tip end side
of the display support member can be a circle.

[0022]The display support member can be formed with a groove extending in
the longitudinal direction. In this embodiment the display support member
holding part can have a guide roller that is in contact with a surface of
the display support member, with the surface being formed with the
groove. A part of the display support member, the part having the groove,
can be the anti-rotation-shape part, wherein the guide roller is the
abutting part.

[0023]The display support member holding part can have a driving source
that moves the display support member. In this configuration a drive
transmission part of the driving source is in contact with the display
support member.

[0024]The holding means can be configured to hold the drive transmission
part toward the display support member.

[0025]The display support member can have a shape curved in the
longitudinal direction so that the shape extends along a head of the
user. In this configuration the image display unit can be moved in a
locus corresponding to the curved shape, between the projecting position
and the retracted position.

[0026]The display support member holding part can comprise a display
support member housing that houses the display support member at the
retracted position.

[0027]Another aspect of the invention is directed to wearable display
systems. An embodiment of such a system comprises a wearable display unit
such as any of the configurations summarized above. The system also
includes a head mounting member that is mounted on a head of a user for
holding the head inside of the head mounting member by an elastic force
of the head mounting member. The wearable display unit can have an
attachment that is fixed to the display support member holding part and
that can be coupled to and removed from a part of the head mounting
member.

[0028]Another aspect of the invention is directed to wearable display
units having an image display unit for displaying an image in front of a
user's eye and the image display unit that can be arranged near the
user's eye. An embodiment of such a unit comprises a display support
member that is curved in a shape extending along a shape of a head and is
fixed to the image display unit. The unit also includes a display support
member holding part that slidably holds the display support member such
that the display support member can move along a locus corresponding to
its curved shape, between a projecting position where the image display
unit can be positioned in front of the eye of the user and a retracted
position where the image display unit has been retracted from the front
of the eye of the user.

[0029]In a wearable display unit according to any of the configurations
summarized above, the image display unit can be fixed to the display
support member such that a visual surface of the image display unit can
swing between a displayable position where the display screen of the
image display unit faces the eye of the user and a non-displayable
position where the display screen is inclined at an angle larger than or
equal to a certain angle with a line of sight of the user's eye. The
wearable display unit can further comprise a detection means that detects
whether the image display unit is in the displayable position or in the
non-displayable position. The wearable display unit also can include a
driving means that makes the display support member slide, and a control
means that makes the driving means drive the display support member such
that the display support member moves from the projecting position to the
retracted position, when the detection means detects that the image
display unit moves from the displayable position to the non-displayable
position in a state that the display support member is in the projecting
position.

[0030]In another embodiment the wearable display system comprises a
wearable display unit according to any of the configurations summarized
above, and a headphone having a speaker and a headphone arm connected to
the speaker, and that can be mounted on a head. The wearable display unit
can have an attachment that can be coupled to and removed from the
headphone. The wearable display unit and the headphone can have
respective electric connection parts that can be electrically connected
and disconnected from each other.

[0031]The wearable display unit can have an outside connection part for
receiving at least electric power, an image signal and an audio signal
from the outside. The wearable display unit can be configured to send at
least the audio signal out of the electric power, the image signal, the
audio signal and the like received through the outside connection part,
to the electric connection part (hereinafter, referred to as a
"headphone-side electric connection part") of the headphone through the
electric connection part (hereinafter, referred to as a "display-side
electric connection part") of the wearable display unit. In that case,
the headphone-side electric connection part may be a headphone cable
having electric contacts at its end.

[0032]The headphone can have an outside connection part for receiving at
least electric power, an image signal and an audio signal from the
outside. The headphone can be configured to send at least the electric
power and the image signal out of the electric power, the image signal,
the audio signal and the like received through the outside connection
part to the electric connection part (hereinafter, referred to as a
"display-side electric connection part") of the wearable display unit
through the electric connection part (hereinafter, referred to as a
"headphone-side electric connection part") of the headphone. In that
case, the display-side electric connection part may be a display cable
having electric contacts at its end.

[0033]Further, the display-side electric connection part may be provided
in the attachment such that the display-side electric connection part is
connected to the headphone-side electric connection part when the
attachment is coupled to the headphone.

[0034]In yet another embodiment each of left and right parts of the
headphone can be provided with the headphone-side electric connection
part. The headphone-side electric connection part can have a plurality of
electric contacts arranged in a predetermined direction. The order of
arrangement of the plurality of electric contacts in the headphone-side
electric connection part provided in one of the left and right parts can
be reversed in a vertical direction from an order of arrangement of the
plurality of electric contacts in the headphone-side electric connection
part provided in the other of the left and right parts, in a state that
the headphone is mounted on the head.

[0035]In yet another embodiment each of left and right parts of the
headphone can be provided with the headphone-side electric connection
part. The headphone-side electric connection part can have a plurality of
electric contacts arranged in a predetermined direction. The order of
arrangement of the plurality of electric contacts in the headphone-side
electric connection part provided in one of the left and right parts can
be reversed in a horizontal direction from an order of arrangement of the
plurality of electric contacts in the headphone-side electric connection
part provided in the other of the left and right parts, in a state that
the headphone is mounted on the head and surfaces in which the electric
contacts are arranged are seen from fronts of the surfaces.

[0036]The attachment can relatively move within a certain width in a
certain direction with respect to the headphone to which the attachment
is coupled. At least either the plurality of the electric contacts in the
headphone-side electric connection part or the plurality of the electric
contacts in the display-side connection part can have a certain width in
the certain direction.

[0037]The attachment of the wearable display unit can have a coupling
means that is deformed to be coupled with a part of the headphone. In
this configuration or in other configurations, the attachment of the
wearable display unit can be coupled to and removed from a part of the
speaker on a side opposite to a side contacting with the head. The part
of the speaker can be provided with the electric contacts of the
headphone-side electric connection part, and the attachment can be
provided with the electric contacts of the display-side electric
connection part. The electric contacts can be connected to the electric
contacts of the headphone-side electric connection part when the
attachment is coupled to the part. The attachment can be provided with a
circuit that processes the image signal and sends the processed image
signal to the image display unit.

[0038]In another embodiment the headphone has a pair of speakers as the
speaker, and the headphone arm connects the pair of speaker with each
other. Each of the pair of speakers can be formed with a coupling portion
to which the attachment can be coupled. The wearable display system
further can comprise an external member that is coupled to the coupling
portion of one speaker of the pair of speakers to cover the coupling
portion, when the other speaker is coupled with the attachment at the
coupling portion of that speaker. In this and other configurations the
attachment can be formed with a hollow portion on a side of a speaker
when the attachment is coupled to the speaker. The external member can be
formed with a hollow portion at a position corresponding to the hollow
portion of the attachment, with the hollow portion formed in the external
member having the same shape and size as ones of the hollow portion of
the attachment.

[0039]In yet another embodiment the display support member holding part is
coupled to the attachment in a relatively rotatable manner.

[0040]At least a part of the coupling means may be made of an elastic
material so that the coupling means is elastically deformed to grasp the
headphone arm of the headphone or to be coupled into the speaker of the
headphone. Further, the coupling means may comprise first and second
grasping members for sandwiching a part of the headphone arm from both
sides, and a pressing member that presses the second grasping member
toward the first member. When the coupling means is deformed as a result
of movement of the second grasping member, a part of the headphone arm is
grasped between the first grasping member and the second grasping member.
In this configuration the coupling means may have a groove member having
a pair of side walls that are opposed to each other. One of the side
walls of the groove member becomes the first grasping member. A screw
member that is screwed and coupled into the other side wall of the groove
member becomes the pressing member. Alternatively, an elastic member
fixed to the other side wall may become the pressing member. The second
grasping member may be fixed to the tip end of the screw member or the
elastic member.

[0041]Further, in any of the above-summarized wearable display units, some
portion in a part ranging from the attachment to the display support
member holding part may be formed with a clearance part that extends in a
direction including a directional component receding from a headphone
speaker connected to the headphone arm, so that the display support
member holding part keeps away from the headphone speaker when the
attachment is coupled to the headphone arm.

[0042]Further, any of the above-summarized wearable display units may
further comprise a display unit displacement means that changes the
position and/or the direction of the image display unit in relation to
the attachment.

[0043]Further, in any of the above-summarized wearable display units, it
is desirable that at least the external shape of the image display unit
is symmetrical in the up-down direction in a state that the attachment is
coupled to the headphone arm.

[0044]Further, any of the above-summarized wearable display units may
further comprise a detection means that detects whether the attachment
has been coupled to the side of the right ear or the side of the left ear
of the headphone arm. The unit may further comprise a display control
means that turns an output image upside down based on a detection result
of the detection means. When the fixing position of the attachment is
changed, the top and the bottom of the image display unit are reversed
accordingly. Thus, as this detection means, a gravity sensor may be used
that detects up-and-down inversion. Or, in the case where the attachment
is provided with the electric contacts of the display-side electric
connection part, an electric current sensor may be used as the detection
means. Here, the electric current sensor detects whether these electric
contacts in the attachment are electrically connected with the electric
contacts of the headphone-side electric connection on one of the left and
right sides of the headphone.

[0045]Another embodiment of a wearable display unit further comprises an
attachment that is provided in the display support member holding part
and that can be coupled to and removed from the headphone. An electric
connection part is provided in the attachment and connected to electric
contacts provided in the headphone when the attachment is coupled to the
headphone.

[0046]The attachment can be provided with a display unit displacement
means that can change a position and/or a direction of the image display
unit in relation to the attachment. In this configuration the electric
connection part has lead wires, and lead wires of the electric connection
part are arranged in the attachment and the display unit displacement
means.

[0047]Another embodiment of a wearable display unit further comprises an
attachment that can be coupled to and removed from a speaker of a
headphone. An electric connection part can be included that can be
electrically connected to and disconnected from a circuit provided in the
headphone.

[0048]According to another aspect of the invention, headphones are
provided. An embodiment comprises a pair of speakers and a headphone arm
connecting the pair of speakers with each other. The embodiment further
comprises electric connection parts provided in respective portions of
the pair of speakers of the headphone arm. Each of the electric
connection parts can be electrically connected to a wearable display unit
having an image display unit for displaying an image in front of an eye
of a user. The image display of which can be arranged near a user's eye,
in such a manner that the electric connection can be disconnected.

[0049]The headphone arm can be formed with coupling portions at respective
portions on sides of the pair of speakers, wherein the display unit can
be coupled to and removed from each coupling portion. Each of the
coupling portions can be provided with electric contacts of the electric
connection that are connected to electric contacts provided in the
wearable display unit when the wearable display unit is coupled to the
coupling portion in question.

[0050]Another aspect of the invention is directed to headphones that
comprise a speaker and a headphone arm connected with the speaker. In an
embodiment the speaker is formed with a coupling portion to which a
wearable display unit having an image display unit for displaying an
image can be coupled in a removable manner. The coupling portion can be
provided with an electric connection part that can be electrically
connected to and disconnected from a circuit provided in the wearable
display unit.

[0051]An auxiliary holding part can be provided at a position of the
display support member or a position of the display support member
holding part such that the auxiliary holding part is outside a field of
vision of the user when a center of the field of vision is in a visual
surface of the image display unit and the auxiliary holding part presses
against the user's head. A pressing force generation means can be
included that uses an elastic force and/or an electromagnetic force to
generate a pressing force at the auxiliary holding part for pressing
against the user's head.

[0052]Another embodiment of a wearable display unit can further comprise
an auxiliary holding part that is provided in the display support member
or the display support member holding part, in a neighborhood of a
temporal part of the head on which the wearable display unit is mounted.
The auxiliary holding part can be configured to press against the
temporal part.

[0053]The wearable display unit further can comprises a pressing force
generation means that uses an elastic force and/or an electromagnetic
force to generate a pressing force at the auxiliary holding part for
pressing against the user's head. The auxiliary holding part can be
provided in such a manner that the auxiliary holding part can be
displaced between a pressing position where the auxiliary holding part
can press against the head and a retracted position where the auxiliary
holding part cannot press against the head. The wearable display unit can
further comprise a pressing force detection means that detects a level of
a pressing force that the auxiliary holding part at the pressing position
applies to the head. The pressing force generation means can be
configured to control the pressing force such that the level detected by
the pressing force detection means is kept within a predetermined range.

[0054]The display support member holding part can comprise a display
support member housing part that houses the display support member. The
display support member housing part can be configured to hold the display
support member slidably between a projecting position where the image
display unit is held in front of an eye of a user and a housed position
where at least a part of the display support member retracted from the
front of the eye of the user is housed in the display support member
housing part. The auxiliary holding part can be configured to be at the
retracted position when the display support member is at the housed
position. The auxiliary holding part can be at the pressing position when
the display support member is at the projecting position.

[0055]Another embodiment of a wearable display unit further comprises an
attachment for fixing the display support member holding part to the head
mounting member that is to be mounted on the user's head. The embodiment
further includes an inclination adjustment means, configured to adjust an
inclination of the display support member to the attachment, within a
plane including a direction of action of the pressing force and the
attachment. The inclination adjustment means can comprise a projection
length adjustment means that adjusts a length of projection of the
auxiliary holding part with respect to the display support member or the
display support member holding part.

[0056]The inclination adjustment means can comprise a distance adjustment
means that adjusts a distance from the attachment to the display support
member holding part at a portion connecting the attachment and the
display support member holding part.

[0057]The pressing force generation means can be arranged in the
attachment or in a neighborhood of the attachment, to generate a force
that makes a side of the image display unit of the display support member
incline toward a direction of action of the pressing force.

[0058]The wearable display unit according to any of various embodiments
can further comprise a joint that fixes the display support member
holding part to the attachment in such a manner that the display support
member holding part can swing in a plane including a direction of action
of the pressing force and the attachment.

[0059]In yet another embodiment of a wearable display unit the wearable
display unit further comprises an attachment that is fixed to a head
mounting member that is mounted on a head of the user. The unit further
comprises a joint part that fixes the display support member holding part
to the attachment in such a manner that the display support member can
swing in relation to the attachment, around a plurality of virtual axes
having different directions from one another. In the joint part, the
torque required for swinging around at least one virtual axis among the
plurality of virtual axes can be different from the torque required for
swinging around an of the other virtual axes. Here, the "virtual axis"
conceptually includes not only an axis as a center of rotation of a joint
structure that has an actual axis but also a center of rotation of a
joint structure that does not have an actual axis.

[0060]The joint portion can comprise a first joint portion that holds the
display support member holding part on the attachment such that the
display support member can swing in relation to the attachment around a
first virtual axis among the plurality of virtual axes. The joint portion
can further include a second joint portion that holds the display support
member holding part on the attachment such that the display support
member can swing in relation to the attachment around a second virtual
axis perpendicular to the first virtual axis.

[0061]The first joint part can comprise a base-side member that is fixed
to or formed integrally with the attachment and a swing-side member that
is fixed to the base-side member in such a way that the swing-side member
can relatively rotate in relation to the base-side member around the
first virtual axis. The second joint part can comprise a swing-side
member that is fixed to or formed integrally with the display support
member holding part and a base-side member that is fixed to the
swing-side member in such a way that the base-side member can relatively
rotate in relation to the swing-side member around the second virtual
axis. In that case, it is favorable that the swing-side member of the
first joint part and the base-side member of the second joint part be
made of the same material.

[0062]One of the plurality of virtual axes can be a virtual axis around
which the image display unit fixed to the display support member swings
in a direction including a vertical direction in a state that the head
mounting member is mounted on a head of the user and the attachment is
coupled to the head mounting member. The torque required for swinging
around the virtual axis in question desirably is larger than the torque
required for swinging around the other virtual axes of the plurality of
virtual axes.

[0063]In a device described in Patent Document 1, a part of the signal
cables of the display device unit is fixed to the head mounting belt, and
the fixing position of the display device unit on the head mounting belt
can be changed. However, in a case in which the head mounting belt has
the same function as a headphone, the wiring cables hang from the head
mounting belt (i.e. the headphone) and wiring cables hang from the
display device unit also. Thus, it is not convenient to use the head
mounting belt. This problem is solved by any of various embodiments of a
wearable display system as summarized above. An exemplary embodiment
comprises a headphone that can be mounted on a head and that comprises a
speaker and a headphone arm connected with the speaker. The embodiment
includes a wearable display unit that comprises an image display unit,
which can be arranged near a user's eye, and can be coupled to the
headphone. The wearable display unit has an attachment that can be
coupled to and removed from the headphone. The wearable display unit and
the headphone have respective electric connection parts that can be
electrically connected and disconnected with and from each other.

[0064]Another embodiment of a wearable display unit includes an image
display unit that can be arranged near a user's eye and that displays an
image in front of a user's eye. The wearable display unit further
comprises an attachment that can be coupled to and removed from a
headphone. The unit further comprises a holding part that connects the
image display unit to the attachment. An electric connection part is
provided in the attachment, with the electric connection part being
connected to electric contacts provided in the headphone whenever the
attachment is coupled to the headphone.

[0065]Another embodiment of a wearable display unit includes an image
display unit that can be arranged near a user's eye and that displays an
image. The unit comprises an attachment that can be coupled to and
removed from a speaker of a headphone that can be mounted on a head. An
electric connection part is provided that can be electrically connected
to and disconnected from a circuit provided in the headphone.

[0066]In a device described in Patent Document 2, the anti-swing member
interrupts a part of a center of the field of vision of a user's eye when
the user's eye views an image of the image display unit. Consequently,
visibility of surroundings sometimes becomes worse. In view of these
shortcomings, an embodiment of a wearable display unit is provided herein
that displays an image in front of an eye of a user. The unit comprises
an image display unit that displays an image. A holding part is provided
that can hold the image display unit at a position in front of the eye of
the user. An attachment is used for fixing the holding part to a head
mounting member that is mounted on the head of the user. An auxiliary
holding part is provided on the holding part at a position that is
outside a field of vision of the user when a center of the field of
vision of the user lies within a visual surface of the image display
unit, with the auxiliary holding part being pressed against the user's
head. The unit further comprises a pressing force generation means that
uses an elastic force and/or an electromagnetic force to generate a
pressing force at the auxiliary holding part so that the auxiliary
holding part presses against the head.

[0067]Another embodiment of a wearable display unit comprises an image
display unit that displays an image, and a holding part that can hold the
image display unit at a position in front of the eye of the user. An
attachment is provided that fixes the holding part to a head mounting
member that is mounted on the user's head. An auxiliary holding part is
provided on the holding part in a neighborhood of a temporal part of the
head on which the head mounting member is mounted, with the auxiliary
holding part pressing against the temporal part.

[0068]In a device as described in Patent Document 3, swinging of the image
display unit in the vertical direction and in the horizontal direction is
realized by means of a spherical seat provided in a connection part
between the display support member and the coupling portion. Thus,
swinging in any direction requires the same torque. As a result, if the
torque required for swinging in the horizontal direction is made smaller
so that a smaller force can produce swinging in the horizontal direction,
the torque required for swinging in the vertical direction becomes
smaller at the same time. As a result, sometimes the image display unit
moves downward automatically owing to its own weight. On the other hand,
if the torque required for vertical swinging is made larger, the torque
required for horizontal swinging becomes larger at the same time. As a
result, it becomes difficult to adjust the position horizontally. Thus,
with a device as disclosed in Patent Document 3, difficult operation is
required for adjusting the position of the image display unit. To solve
this problem, an embodiment of a wearable display unit is provided that
has an image display unit for displaying an image in front of an eye of a
user and that can be arranged near a user's eye. The wearable display
unit comprises an attachment to be coupled to a head mounting member that
is mounted on a head of the user. The unit also includes a holding part
having one end fixed to the image display unit while the other end of the
holding part extends to a position opposed to the attachment. The unit
also comprises a joint part that fixes the holding part to the attachment
such that the holding part can swing relatively to the attachment around
a plurality of virtual axes extending in respective directions different
from one another. In the joint part, the torque required for swinging
around at least one virtual axis among the plurality of virtual axes is
different from the torque required for swinging around the other virtual
axes.

[0069]In various embodiments as described herein, anti-rotation means is
provided. As a result, even in a state in which the display support
member can move in the neighborhood of the projecting position, it is
possible to prevent rotation of the display support member in relation to
the display support member holding part with respect to rotation whose
direction is within a plane perpendicular to the longitudinal direction
of the display support member.

[0070]Further, one cable can be used for supplying an audio signal
supplied to a headphone and an image signal supplied to the wearable
display unit, thereby improving the usability of the wearable display
system.

[0071]Further, various embodiments can provide a wearable display unit
that can suppress vibration of the image display unit is suppressed
without damaging visibility of surroundings. In various embodiments, in
the joint part for fixing the holding part of the image display unit
swingably to the attachment, the torque required for swinging around one
virtual axis among a plurality of virtual axes is different from the
torque required for swinging around the other virtual axes. Thus,
automatic displacement of the image display unit can be prevented, and
the position of the image display unit can be adjusted by easy operation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0072]FIG. 1 is a perspective view showing a wearable display system
having an image display unit of a first embodiment, the image display
unit of which can be arranged near a user's eye;

[0073]FIG. 2 is a partially-cutaway plan view showing main parts of the
wearable display system (in a state of a projecting position) of the
first embodiment;

[0074]FIG. 3 is a partially-cutaway plan view showing the main parts of
the wearable display system (in a state of a retracted position) of the
first embodiment;

[0077]FIG. 6 is a cross section showing an attachment of the wearable
display unit of the first embodiment;

[0078]FIG. 7 is a circuit block diagram of the wearable display unit of
the first embodiment;

[0079]FIG. 8 is a cross section showing a first variant of the display
support member and its holding part of the wearable display unit of the
first embodiment;

[0080]FIG. 9 is a cross section showing a second variant of the display
support member and its holding part of the wearable display unit of the
first embodiment;

[0081]FIG. 10 is a cross section showing a third variant of the display
support member and its holding part of the wearable display unit of the
first embodiment;

[0082]FIG. 11 is an explanatory view for explaining difference in working
methods according to a position of a groove to be formed in a curved
bar-shaped member;

[0083]FIG. 12 is a cross section showing a fourth variant of the display
support member and its holding part of the wearable display unit of the
first embodiment;

[0084]FIG. 13 is a cross section showing a fifth variant of the display
support member and its holding part of the wearable display unit of the
first embodiment;

[0085]FIG. 14 is a cross section showing a sixth variant of the display
support member and its holding part of the wearable display unit of the
first embodiment;

[0086]FIG. 15 is a cross section showing the sixth variant of the display
support member and its holding part of the wearable display unit of the
first embodiment, FIG. 15A being a cross section showing the display
support member and a slide shoe seen along the A-A line in FIG. 14, and
FIG. 15B a cross section showing the display support member and the slide
shoe seen along the B-B line in FIG. 14.

[0087]FIG. 16 is a perspective view showing a seventh variant of the
display support member and its holding part of the wearable display unit
of the first embodiment;

[0088]FIG. 17 is a cross section showing the seventh variant of the
display support member and its holding part of the wearable display unit
of the first embodiment, FIG. 17A being a cross section showing the
display support member and a slide shoe seen along the A-A line in FIG.
16 and FIG. 17B a cross section showing the display support member and
the slide shoe seen along the B-B line in FIG. 16;

[0089]FIG. 18 is a cross section showing a variant of the display support
member and its driving part of the wearable display unit of the first
embodiment;

[0090]FIG. 19 is a perspective view showing a wearable display system
having a image display unit (in a coupled state) of a second embodiment,
the image display unit of which can be arranged near a user's eye;

[0091]FIG. 20 is a perspective view showing the wearable display system
(in a non-coupled state) of the second embodiment;

[0093]FIG. 22 is a circuit block diagram of the wearable display system of
the second embodiment;

[0094]FIG. 23 is a cross section showing a first variant of an attachment
of the wearable display system of the second embodiment;

[0095]FIG. 24 is a cross section showing a second variant of the
attachment of the wearable display system of the second embodiment;

[0096]FIG. 25 is a perspective view showing a variant of headphones of the
wearable display system of the second embodiment;

[0097]FIG. 26 is a perspective view showing a wearable display system
having an image display unit (in a coupled state) of a third embodiment,
the image display unit of which can be arranged near a user's eye;

[0098]FIG. 27 is a perspective view showing the wearable display system
(in a non-coupled state) of the third embodiment;

[0099]FIG. 28 is a circuit block diagram of the wearable display system of
the third embodiment;

[0100]FIG. 29 is a perspective view showing a wearable display system
having an image display unit (in a non-coupled state) of a fourth
embodiment, the image display unit of which can be arranged near a user's
eye;

[0101]FIG. 30 is a cross section showing main parts of the wearable
display system of the fourth embodiment;

[0102]FIG. 31 is a cross section showing an attachment of the wearable
display system of the fourth embodiment;

[0103]FIG. 32 is an explanatory view showing arrangement of electric
contacts in coupling portions on the left and right sides of the wearable
display system of the fourth embodiment;

[0104]FIG. 33 is a circuit block diagram of the wearable display system of
the fourth embodiment;

[0105]FIG. 34 is a cross section showing a displacement mechanism of the
wearable display system of the fourth embodiment;

[0106]FIG. 35 is a perspective view showing a wearable display system
having an image display unit of a fifth embodiment, the image display
unit of which can be arranged near a user's eye;

[0107]FIG. 36 is a circuit block diagram of the wearable display system of
the fifth embodiment;

[0108]FIG. 37 is a perspective view showing a wearable display system
having an image display unit of a sixth embodiment, the image display
unit of which can be arranged near a user's eye;

[0109]FIG. 38 is a cross section showing a speaker, an attachment and a
displacement mechanism of the wearable display system of the sixth
embodiment;

[0110]FIG. 39 is a cross section showing a speaker and an outer cap of the
wearable display system of the sixth embodiment;

[0111]FIG. 40 is a cross section showing a speaker and an attachment of a
variant of the wearable display system of the sixth embodiment;

[0112]FIG. 41 is a perspective view showing a wearable display system
having an image display unit of a seventh embodiment, the image display
unit of which can be arranged near a user's eye;

[0113]FIG. 42 is a cutaway plan view showing main parts of the wearable
display system of the seventh embodiment;

[0114]FIG. 43 is an explanatory view for explaining a driving mechanism of
an auxiliary holding part of the wearable display system of the seventh
embodiment;

[0115]FIG. 44 is a circuit block diagram of the wearable display system
having an image display unit of the seventh embodiment, the image display
unit of which can be arranged near a user's eye;

[0116]FIG. 45 is a perspective view showing a wearable display system
having an image display unit (in a state of a projecting position) of an
eighth embodiment, the image display unit of which can be arranged near a
user's eye;

[0117]FIG. 46 is a perspective view showing the wearable display system
(in a state of a housed position) of the eighth embodiment;

[0118]FIG. 47 is a perspective view showing a wearable display system
having an image display unit (in a state of a projecting position) of a
ninth embodiment, the image display unit of which can be arranged near a
user's eye;

[0119]FIG. 48 is a perspective view showing an auxiliary holding part of
the wearable display system of the ninth embodiment;

[0120]FIG. 49 is a perspective view showing a first variant of the
wearable display system of the ninth embodiment;

[0121]FIG. 50 is a perspective view showing a second variant of the
wearable display system of the ninth embodiment;

[0122]FIG. 51 is a perspective view showing a wearable display system
having an image display unit of a tenth embodiment, the image display
unit of which can be arranged near a user's eye;

[0123]FIG. 52 is a cutaway plan view showing main parts of the wearable
display system of the tenth embodiment;

[0125]FIG. 54 is a perspective view showing a distance adjusting member of
the wearable display system of the tenth embodiment;

[0126]FIG. 55 is a perspective view showing a wearable display unit having
an image display unit of an eleventh embodiment, the image display unit
of which can be arranged near a user's eye;

[0127]FIG. 56 is a cutaway plan view showing main parts of the wearable
display unit of the eleventh embodiment;

[0128]FIG. 57 is a cross section taken along the A-A line in FIG. 56; and

[0129]FIG. 58 is a cross section showing a variant of a joint part of the
wearable display unit of the eleventh embodiment.

DETAILED DESCRIPTION

[0130]Various embodiments of the wearable display system will be
described.

First Embodiment

[0131]In the beginning, will be described a first embodiment of a wearable
display system having an image display unit, the image display unit of
which can be arranged near a user's eye.

[0132]As shown in FIGS. 1-3, the wearable display system of the present
embodiment comprises: headphones 10 that can be mounted on the head H of
a user; and a wearable display unit 20 that is fixed to the headphones
10. FIG. 1 is a perspective view showing the wearable display system of
the first embodiment. FIG. 2 is a cutaway plan view showing main parts of
the wearable display system (in a state of a projecting position). And,
FIG. 3 is a cutaway plan view showing the main parts of the wearable
display system (in a state of a retracted position).

[0133]The headphones 10 of this wearable display system comprises: left
and right speakers 11L and 11R; and an arm 12 that connects the left and
right speakers 11L and 11R with each other. Both end portions of the arm
12 are curved such that these end portions can be placed on the left and
right ears of the user. Thus, these end portions form earpieces 13L and
13R. The headphones 10 are rear-arm type headphones whose arm 12 is
positioned around the back of the head of a user.

[0134]The wearable display unit 20 comprises: an image display unit 21
that displays an image in front of a user's eye; a display support member
27 that fixes the image display unit 21 at its end portion; a display
support member holding part 30 that supports the display support member
27 slidably; and an attachment 40 that fixes the display support member
holding part to the headphone arm 12.

[0135]The display support member 27 has a bar shape curved smoothly at a
radius of curvature R. When the wearable display unit 20 is mounted on
the head H of the user, the center of curvature of the display support
member 27 lies inside the head H. This display support member 27 is
supported by the display support member holding part 30 such that the
image display unit 21 can move between a retracted position d (FIG. 3)
and a projecting position c (FIGS. 1 and 2) along a locus B corresponding
to the curved shape of the display support member 27. At the retracted
position d, the display support member 27 is housed in the display
support member holding part 30. And, at the projecting position c, the
display support member 27 projects from the display support member
holding part 30 and the image display unit 21 can display an image in
front of a user's eye. Further, the image display unit 21 is fixed at the
end portion of the display support member 27 in such a way that the
display unit 21 can swing in the direction of the arrow A between a
displayable position a where a visual surface of the image display unit
21 faces a user's eye and non-displayable position b where the display
screen is inclined at a angle larger than or equal to a certain angle
with the line of sight of the user's eye. The length of the display
support member 27 is determined such that the display screen of the image
display unit 21 can be at a distance of 20 mm or more from the user's eye
when the image display unit 21 is at the displayable position. Here, the
distance of 20 mm or more is determined considering the case where a user
uses a pair of glasses. Thus, since the display support member 27 has the
curved shape and the image display unit 21 can move depicting the locus B
corresponding to the curved shape, the image display unit 21 can move
safely without interfering with the head.

[0136]As shown in FIGS. 2 and 3, the image display unit 21 comprises: a
display device 22; an optical system 23 for leading an image displayed by
the display device 22 to a user's eye; a display unit position detection
sensor 24 for detecting whether the image display unit 21 is in the
above-mentioned displayable position or in the non-displayable position;
and a display unit housing 25 that houses these components. The display
unit housing 25 is formed with a fixing member 26 that is fixed to the
end portion of the display support member 27. The display unit position
detection sensor 24 is an optical sensor and detects whether the image
display unit 21 is in the displayable position or the non-displayable
position based on a change of a relative position of the display support
member 27 within the display unit housing 25.

[0137]The display support member holding part 30 comprises: a display
support member housing 31 formed with an internal space that can house
the display support member 27; guide rollers 34a and 34b that can support
the display support member 27 slidably; a driving roller 35a that makes
the display support member 27 slide; a display support member driving
motor 35b that makes the driving roller 35a rotate; a retraction
detection sensor 37a that detects whether the display support member 27
is in the above-mentioned retracted position d or not; a projection
detection sensor 37b that detects whether the display support member 27
is in the above-mentioned projecting position c or not; and a display
support member drive switch 36 for instructing operation of the display
support member driving motor 35b.

[0138]The internal space of the display support member housing 31 is
curved correspondingly to the curved shape of the display support member
27. In one end (hereinafter, referred to as a forward end) of the display
support member housing 31, there is formed a display support member
insertion hole 32 through which the display support member 27 enters and
exits the display support member housing 31. And, in the other end
(hereinafter, referred to as a rear end) of the display support member
housing 31, there is formed a clearance part 33. The clearance part 33 is
a part that extends in a direction for keeping away from the headphone
arm 12 so as to prevent interference between the speaker 11L or 11R of
the headphones 10 and the display support member housing 31 when the
attachment 40 is coupled to the headphone arm 12. In the neighborhood of
the display support member insertion hole 32 of the display support
member housing 31, a pair of guide rollers 34a, 34b is provided in each
of two places along a moving path B of the display support member 27.
Between the guide rollers 34a on the forward end side and the guide
rollers 34b on the rear end side, the driving roller 35a is provided on
the inner side of the curved display support member 27, i.e. on the side
of the user's head.

[0139]As shown in FIGS. 4 and 5, the shape of the outer periphery of the
display support member 27 in a cross section perpendicular to its
longitudinal direction has parts of different distances from the center
of gravity of the cross section. In other words, that shape is not a
circle. Or, in more concrete terms, the shape is nearly circular, but
formed with grooves 28a and 28b on the inner side and the outer side
(i.e. the other side) of the curved display support member 27
respectively, to form anti-rotation-shape parts. Thus, the shape of the
cross section of the display support member 27 is not circular in order
to prevent rotation around its longitudinal axis. The grooves 28a and 28b
on the internal and outer sides of the display support member 27 extend
in the longitudinal direction of the display support member 27. Here,
FIG. 4 shows the cross section taken along the C-C line in FIG. 2, and
FIG. 5 the cross section taken along the D-D line in FIG. 2.

[0140]As shown in FIG. 4, the above-mentioned pair of guide rollers 34a,
34a (34b, 34b) is in contact with the insides of the grooves 28a and 28b
(i.e. the anti-rotation-shape parts) of the display support member 27 and
thus becomes abutting parts that abut on the anti-rotation-shape parts.
Each guide roller 34a (34b) is rotatably mounted on a roller shaft 34c
provided in the display support member housing 31. Further, the
above-mentioned driving roller 35a also is in contact with the bottom of
the groove 28a on the inner side of the display support member 27, as
shown in FIG. 5. The driving roller 35a is mounted on a driving shaft of
the display support member driving motor 35b fixed within the display
support member housing 31. Thus, by arranging the driving roller 35a and
the display support member driving motor 35b on the inner side of the
display support member 27, the heavy component is positioned near to the
head of a user as shown in FIG. 2. This can improve stability at the time
of movement of the head and reduce extension of the display support
member housing 31 toward the outer side of the display support member,
i.e. in the direction of getting away from the head.

[0141]As shown in FIG. 6A, the attachment 40 is made of an elastic
material such as resin and is formed to have a C-shaped cross section. A
space d of the opening of the C-shape is slightly larger than the minor
axis γ2 of the headphone arm 12 whose cross section is an ellipse,
although smaller than the major axis γ1 of the headphone arm 12.
Thus, the headphone arm 12 can be easily put into the attachment 40 by
making the minor axis γ2 of the headphone arm 12 vertical and
thereafter by bringing the headphone arm 12 close to the opening of the
attachment 40 in the X direction shown in the figure. Then, by relatively
rotating the headphone arm 12 through 90 degrees, the headphone arm 12 is
completely fitted in the attachment 40 as shown in FIG. 6B. At that time,
the attachment 40 is elastically deformed to be slightly widened, and
thus the attachment 40 grasps the headphone arm 12 tightly. As a result,
the wearable display unit 20 has been fixed to the headphone arm 12.

[0142]Thus, according to the present embodiment, the wearable display unit
20 can be fixed to the headphone arm 12 by simply grasping the headphone
arm 12. As a result, the wearable display unit 20 can be used in many
different ways. Further, in the present embodiment, the attachment 40
grasps the headphone arm 12 by its elastic deformation, and can adapt to
a headphone arm 12 having a slightly different cross section. Further,
the headphones 10 do not have a special fixing structure for the wearable
display unit, and thus the beauty of the headphones is improved when it
is used as a single item.

[0143]As shown in FIGS. 2 and 3, the clearance part 33 of the display
support member housing 31 is provided with a displacement mechanism 50.
The displacement mechanism 50 is provided for changing the position and
direction of the image display unit 21 relatively to the attachment 40.
The displacement mechanism 50 comprises a ball 51 provided in the
attachment 40 and a ball socket 52 formed in the clearance part 33 of the
display support member housing 31. Frictional force larger than a certain
magnitude acts between the ball 51 and the ball socket 52. Thus, the ball
socket 52 can not rotate relatively to the ball 51 unless turning force
larger than a certain magnitude acts on the ball socket 52 in relation to
the ball 51.

[0144]Since the displacement mechanism comprises the ball 51 and the ball
socket 52 as described above, the display support member holding part 30,
the display support member 27 held by the display support member holding
part 30 and the image display unit 21 fixed to the display support member
27 can be displaced around each of three independent axes in the
three-dimensional space.

[0145]This displacement mechanism 50 may be provided between the display
support member holding part 30 and the image display unit 21, or may be
provided in the display support member holding part 30. However, the
displacement mechanism 50 has its own weight. And, it is favorable to
provide the displacement mechanism 50 between the attachment 40 and the
display support member holding part 30 as in the present embodiment, in
order to reduce the moment around the attachment 40 as far as possible.
Further, in the present embodiment, the ball 50 is formed on the side of
the attachment 40. It is needless to say, however, that the ball 50 can
be formed on the side of the display support member housing 31 and the
ball socket 52 on the side of the attachment 40.

[0147]The display support member housing 31 of the display support member
holding part 30 is provided with the driving roller 35a, the display
support member driving motor 35b, the retraction detection sensor 37a,
the projection detection sensor 37b, the display support member drive
switch 36, and in addition, a control system 38 and an image processing
system 39. The control system 38 controls the display support member
driving motor 35b based on signals from the various sensors 24, 37a and
37b and the display support member drive switch 36. The image processing
system 39 sends an image signal to the display device 22 of the image
display unit 21 based on a signal from an external controller C.

[0148]It is possible that the external controller C sends an audio signal
to the headphones 10 through the wearable display unit 20. Or, reversely,
it is possible that the external controller C sends the image signal, a
control signal and the like in addition to the audio signal to the
headphones 10, and the headphones 10 in turn send the image signal, the
control signal and the like among those signals to the wearable display
unit 20. In the case where all the signals are sent to one of the
headphones 10 and the wearable display unit 20 and then signals required
for the other component are sent from the component that has received all
the signals, it is necessary that both components are provided with
respective electric connection parts that can be disconnected, in order
to connect both electrically.

[0149]Next, will be described manipulation and associated operation of the
wearable display unit 20 in the present embodiment.

[0150]First, the attachment 40 of the wearable display unit 20 is coupled
to the headphone arm 12 as described above. Then, the headphones 10 fixed
with the wearable display unit 20 are mounted on the head. At that time,
as shown in FIG. 3, the image display unit 21 of the wearable display
unit 20 is positioned in the non-displayable position b and the display
support member 27 is in the retracted position d.

[0151]Next, when the display support member drive switch 36 of the
wearable display unit 20 is pushed, the control system 38 detects an
ON/OFF state of the display support member drive switch 36 and outputs a
display support member drive control signal to the display support member
driving motor 35b so that the display support member driving motor 35b
starts driving the display support member 27 to project. At that time,
the display support member 27 and the image display unit 21 move along
the locus B corresponding to the curved shape of the display support
member 27. When the display support member 27 reaches the projecting
position c, the projection detection sensor 37b detects this and informs
the control system 38 of this fact. Then, a projection off signal sent
from the control system 38 stops the display support member driving motor
35b, and the display support member 27 stops at the projecting position
c.

[0152]When the image display unit 21 is manually moved from the
non-displayable position b to the displayable position a as shown in
FIGS. 1 and 2 in a state where the display support member 27 is in the
projecting position c, the display unit position detection sensor 24
detects this change of position and informs the control system 38 of this
fact. The control system 38 informs the external controller C of the fact
that the image display unit 21 reaches the displayable position. Then,
the external controller C knows that the wearable display unit 20 is
ready to send the image signal. When a play button of the external
controller C is pushed in this state, the external controller C sends the
image signal to the image processing system 39. The image processing
system 39 in turn sends the image signal to the display device of the
image display unit 21 to reproduce an image based on the image signal.
Here, instead of pushing the display support member drive switch 36 at
the beginning, it may be arranged as follows. Namely, when the play
button of the external controller C is pushed, the external controller C
sends the display support member drive control signal to the control
system 38 to carry out the above-mentioned series of operations.

[0153]To stop the reproduction of the image, the image display unit 21 is
manually moved from the displayable position a to the non-displayable
position b. Then, the display unit position detection sensor 24 detects
this change of position, and informs the control system 38 of this
change. The control system 38 informs the external controller C of the
fact that the image display unit 21 reaches the non-displayable position
b to stop sending of the image signal from the external controller C.

[0154]Next, when the display support member drive switch 36 of the
wearable display unit 20 is pushed, the control system 38 detects an
ON/OFF state of the display support member drive switch 36 and outputs
the display support member drive control signal to the display support
member driving motor 35b so that the display support member driving motor
35b starts driving the display support member 27 to retract. In this
retraction process, the display support member 27 moves along the locus B
corresponding to its own curved shape. When the display support member 27
reaches the retracted position d, the retraction detection sensor 37a
detects this and informs the control system 38 of this fact. Then, a
retraction off signal sent from the control system 38 stops the display
support member driving motor 35b, and the display support member 27 stops
at the retracted position d.

[0155]Thus, in the present embodiment, the display support member 27 and
the image display unit 21 move along the locus corresponding to the
curved shape of the display support member 27. As a result, the display
support member 27 and the image display unit 21 move along the head of a
user, and it is possible to suppress the distance between these
components and the user's head to the minimum distance that does not
cause interference with the user's head. This reduces the possibility
that the image display unit 21 and the like touch other things even when
the user's head moves during movement of the image display unit 21 and
the display support member 27.

[0156]Further, in the present embodiment, when the image display unit 21
does not display an image, the display support member 27 is at the
retracted position where the display support member 27 is housed in the
display support member housing 31. This reduces the moment of the
wearable display unit 20 around the attachment 40 that is coupled to the
headphone arm 12 as a head mounting belt. As a result, it is possible to
reduce swinging of the wearable display unit 20 even if the user's head
moves in a state that the image display unit 21 is retracted and the
user's field of vision is ensured. This improves the comfort of the
mounted wearable display unit 20.

[0157]Further, in the present embodiment, the groove 28a is formed in the
display support member 27 and the guide rollers 34a and 34b and the
driving roller 35a are made to be in contact with the bottom of the
groove 28a. This prevents rotation of the display support member 27
around its longitudinal axis whether the display support member 27 is
moving or not.

[0158]Next, referring to FIGS. 8-17, will be described various variants of
the anti-rotation-shape parts of the above-described wearable display
unit 20 as well as various variants of the abutting parts that abut on
the anti-rotation-shape parts. FIGS. 8-10, 12 and 13 are cross sections
at the respective positions that correspond to the cross section at the
C-C line in FIG. 2. Further, FIG. 11 is an explanatory view for
illustrating difference in working methods according to a position of a
groove to be formed in a curved bar-shaped member.

[0159]In a first variant, the shape of cross section of the display
support member 27a is almost rectangular and a groove is formed in one
side of the display support member 27a. A guide roller 34a on the inner
side of the display support member 27a is in contact with the inside of
the groove 28a formed in one side of the display support member 27a, and
a guide roller 34a on the outer side is in contact with the other side of
the display support member 27a. Thus, in the case of the display support
member 27a having the cross section of the almost rectangular shape also,
it is possible to prevent rotation of the display support member 27a
around its longitudinal axis. Further, even if the groove is formed only
in the inner side of the display support member 27a, it is possible to
control rotation of the display support member 27a as well as its
movement in a direction other than the longitudinal direction, as long as
the guide roller 34a enters the groove 28a on the inner side.

[0160]In this variant and the above-described embodiment, the groove(s) of
the display support member is (are) formed in the inner side or (and) the
outer side, i.e. the left or (and) right side(s) of the display support
member 27, 27a. However, basically same effects can be obtained when
grooves of the display support member are formed instead in the top
and/or the bottom of the display support member 27, 27a.

[0161]However, when a groove is formed in a curved bar-shaped member by
means of a disk-shaped working tool W1, W2 as shown in FIG. 11, a groove
G1 can be formed without changing the direction of the rotation axis of
the disk-shaped working tool W1 in the case where the groove G1 is to be
formed on the inner side and/or the outer side of the curved bar-shaped
member. On the other hand, when a groove G2 is to be formed on a side
perpendicular to the inner side-outer side direction of the curved
bar-shaped member, the direction of the rotation axis of the disk-shaped
working tool W2 should be changed successively as the working tool W2
moves. Thus, from the viewpoint of groove working, it is favorable to
form the groove(s) on the inner side and/or the outer side of the curved
display support member.

[0162]Second and third embodiments are shown in FIGS. 9 and 10
respectively, and, in these embodiments, the cross section of each
display support member 27b, 27c has the shape of a rectangle or
two-tiered vertical and horizontal rectangles in which no groove is
formed. These variants also can prevent rotation of the display support
member 27b, 27c around its longitudinal axis as in the above embodiment
and the first variant. However, these second and third variants do not
have a groove differently from the above embodiment and the first
variant. Accordingly, to control movement of the display support member
27b, 27c in the up-and-down direction, i.e. the direction perpendicular
to the inner side-outer side direction, it is necessary to provide a
guide roller 34c at a position in the up-and-down direction.

[0163]Fourth and fifth variants are shown in FIGS. 12 and 13 respectively.
Each display support member 27c, 27d of these variants has a cross
section of a circle-on-circle shape. In detail, a cross section of the
display support member 27 of the fourth variant has a shape of two
circles tangent to each other. On the other hand, a cross section of the
display support member 27d of the fifth variant has a shape of two
slightly-separated circles having connection parts between them. Each
display support member 27c, 27d of these variants forms a groove 28 at a
part of opposed arcs, and a guide roller 34a is in contact with this
groove 28.

[0164]In sixth and seventh variants shown in FIGS. 14-17, each display
support member 27e, 27a has different cross sections at the tip portion s
at which the image display unit is fixed and at the base portion b on the
other side. Further, each display support member 27e, 27f is supported by
a slide shoe 34e, 34f. Each slide shoe 34e, 34f is fixed to the display
support member insertion hole 32 shown in FIG. 1.

[0165]The display support member 27e of the sixth variant has a cross
section of a circular shape on the side of its tip portion s as shown in
FIG. 15A and a cross section of an elliptical shape on the side of its
base portion b as shown in FIG. 15B. Here, FIG. 15A shows the cross
sections of the display support member 27e and the slide shoe 34e both
taken along the A-A line of FIG. 14. And, FIG. 15B shows the cross
sections of the display support member 27e and the slide shoe 34e both
taken along the B-B line of FIG. 14.

[0166]The shape of the internal surface of the slide shoe 34e through
which the display support member 27e is inserted is an elliptical shape
of the same shape and size as the shape of the cross section of the
display support member 27e on the side of its base portion b. As a
result, when the base portion b of the display support member 27e is at
the position of the slide shoe 34e, or in other words, when the image
display unit is nearly at the projecting position, movement of the
display support member 27e in any direction within a plane perpendicular
to the longitudinal axis of the display support member 27e and rotation
of the display support member 27e in a direction within this plane are
restricted and only movement in the longitudinal direction is possible.
On the other hand, the cross section of the display support member 27e on
the side of its tip portion s has a shape of a circle as described above,
and the diameter of the circle is same as the minor axis of the
elliptical shape on the side of the base portion b. As a result, when the
tip portion s of the display support member 27e is at the position of the
slide shoe 34e, or in other words, when the image display unit is nearly
at the retracted position, movement of the display support member 27e in
any direction within a plane perpendicular to the longitudinal axis of
the display support member 27e is restricted while rotation of the
display support member 27e in a direction within this plane is not
restricted.

[0167]Accordingly, in the case of this variant, when the image display
unit is nearly positioned at the projecting position, the display support
member 27e can not rotate whether the display support member 27e is
moving or not, and thus the image display unit is prevented from
inclining. On the other hand, when, in this variant, the image display
unit is nearly positioned at the retracted position, it is possible to
rotate the display support member 27e such that the image display unit is
inclined suitably. In other words, in the present embodiment, even though
the display support member 27e is in any posture in the neighborhood of
the retracted position, the image display unit assumes the determined
posture at the projecting position. Further, at the projecting position,
lead wires from the display support member 27e have little play in the
display support member housing 31, and there is a possibility that the
lead wires may break when the display support member 27e rotates.
However, the present embodiment prevents rotation of the display support
member 27 when it is nearly at the projecting position, and accordingly
the lead wires can be prevented from breaking

[0168]The display support member 27f of the seventh variant has a cross
section of a circular shape on the side of its tip portion s as shown in
FIG. 17 A and a cross section of an arc shape on the side of its base
portion b as shown in FIG. 17B. Here, FIG. 17A shows the cross sections
of the display support member 27f and the slide shoe 34f both taken along
the A-A line of FIG. 16. And, FIG. 17B shows the cross sections of the
display support member 27f and the slide shoe 34f both taken along the
B-B line of FIG. 16.

[0169]The shape of the internal surface of the slide shoe 34f through
which the display support member 27f is inserted is an arc shape of the
same shape and size as the shape of the cross section of the display
support member 27f on its side of the base portion b. As a result, when
the base portion b of the display support member 27f is at the position
of the slide shoe 34f, or in other words, when the image display unit is
nearly at the projecting position, movement of the display support member
27f in any direction within a plane perpendicular to the longitudinal
axis of the display support member 27f and rotation of the display
support member 27f in a direction within this plane are restricted and
only movement in the longitudinal direction is possible. On the other
hand, the cross section of the display support member 27f on its side of
the tip portion s has a shape of a circle as described above, and the
diameter of the circle is same as the height of the arc (i.e. the height
from the chord as the base) on the side of the base portion. As a result,
when the tip portion s of the display support member 27f is at the
position of the slide shoe 34f, or in other words, when the image display
unit is nearly at the retracted position, movement of the display support
member 27f in any direction within a plane perpendicular to the
longitudinal axis of the display support member 27f is restricted while
rotation of the display support member 27f in a direction within this
plane is not restricted.

[0170]Thus, the present variant can obtain the effects similar to the
sixth variant.

[0171]Next, referring to FIG. 18, will be described a variant of a mode of
fixing the display support member driving motor 35b that makes the
display support member 27 move.

[0172]As shown in FIG. 5, in the above-described embodiment, a motor
fixing wall is formed as a high wall adapted for an external shape of the
casing of the display support member driving motor 35b in order to
prevent shift and swing of the display support member driving motor 35b.
In the present embodiment, the motor fixing wall 35c is made lower so
that the tip side of the display support member driving motor 35b can
swing although it can not shift. At the same time, the tip side of the
display support member driving motor 35b is biased toward the display
support member 27 by means of a spring 35d.

[0173]Generally, in the case where the display support member driving
motor 35b is fixed firmly as in the above-described embodiment, it is
impossible to keep a prescribed contact pressure between the display arm
support member 27 and the driving roller 35a mounted on the end of the
display support member driving motor 35b unless the fixing position of
the display support member driving motor 35b is determined very
precisely. Even if the position of the display support member driving
motor 35b is determined very precisely, the contact pressure changes when
the display support member 27 moves and accordingly the relative distance
between the driving roller 35a and the display support member 27 changes
slightly. Thus, in the case where the contact pressure between the
display support member 27 and the driving roller 35 can not be controlled
to be constant, the driving roller 35a may slip on the display support
member 27 so that the display support member 27 can not be moved by an
intended distance.

[0174]In the present embodiment, the contact pressure between the driving
roller 35a and the display support member 27 is managed to be an intended
contact pressure by holding the driving roller 35a toward the display
support member 27 by means of the spring 35d while allowing the tip
portion, i.e. the driving roller 35a of the display support member
driving motor 35b to move in the direction of approaching to and leaving
from the display support member 27.

[0175]Hereinabove, the first embodiment of the wearable display unit has
been described. However, the display support member does not need to have
a constant curvature as in the above-described embodiment, and for
example, may be curved in a shape like a part of the circumference of an
ellipse. Further, in this embodiment, the locus of the movement of the
image display unit 21 completely coincides with the curved shape of the
display support member 27. However, it is sufficient that the locus of
the image display unit is curved in a shape nearly similar to the curved
shape of the display support member.

[0176]Further, the above-described embodiment has been described taking up
the rear-arm type headphones 10. However, the present invention is not
limited to this and may be applied to a head-arm type that is worn by
putting its arm around the top of a head. Further, the above-described
embodiment is directed to headphones provided with speakers. However, the
present invention can be applied to a head-mounted device as long as the
device has an arm to be mounted on a head to hold the head from its left
and right sides, even if the device is not provided with speakers.

Second Embodiment

[0177]A second embodiment of the wearable display system of which the
image display unit can be arranged near a user's eye will be described
referring to FIGS. 19-22. In each of the below-described embodiments
also, a mechanism for preventing rotation of a display support member is
provided similarly to the first embodiment and its variants. FIG. 19 is a
perspective view showing a wearable display system having an image
display unit (in a coupled state) of the present embodiment, the image
display unit of which can be arranged near a user's eye; FIG. 20 is a
perspective view showing the wearable display system (in a non-coupled
state); FIG. 21 is a cross section taken along the III-III line in FIG.
19; and FIG. 22 is a circuit block diagram of the wearable display
system.

[0178]As shown in FIGS. 19 and 20, the wearable display system of the
present embodiment comprises headphones 110 and a wearable display unit
120 that can be mounted on the headphones 110 and the image display unit
of which can be arranged near a user's eye.

[0179]The headphones 110 comprises: left and right speakers 111L and 111R;
a headphone arm 112 that connects the left and right speakers 111L and
111R with each other; earpieces 113L and 113R provided in the left and
right speakers 111L and 111R respectively; and a cable connection part
(an external connection part) 114. The headphones 110 are rear-arm type
headphones whose headphone arm 112 is positioned around the back of the
head of a user.

[0180]The wearable display unit 120 comprises: an image display unit 121
that displays an image in front of a user's eye; an attachment 140 that
is fixed to the headphone arm 112; a holding part 130 that couples an
image display unit 121 to the attachment 140; and a cable 139 as a
display-side electric connection part for electric connection with the
headphones 110. The holding part 130 comprises: a bar-shaped display
support member 131 whose cross section has an elliptic shape; and a
display support member housing part 133 for housing the display support
member 131. The longitudinal shape of the display support member 131 is
curved correspondingly to a shape of a head of a user. The display
support member housing part 133 has an internal space that can house most
of the display support member 131. The external shape of this wearable
display unit 120 including a display screen of the image display unit 121
is symmetrical about a horizontal plane in a state that the wearable
display unit 120 is mounted horizontally on the head of a user.

[0181]As shown in FIG. 21, the display support member housing part 133
comprises: a display support member housing 136 for housing the display
support member 131; a plurality of bearings 137 that slidably support the
display support member 131; and a driving roller 138 for moving the
display support member 131. In one end of the display support member
housing 136, there is formed a display support member insertion hole 134
for insertion of the display support member 131. And, in the other end of
the display support member housing 136, there is provided the display
cable (the display-side electric connection part) 139 for electric
connection with the headphones 110. And further, at a part connecting to
the attachment 140, there is formed a clearance part 135. This clearance
part 135 serves to avoid interference between the speaker 111L or 111R of
the headphones 110 and the display support member housing 136. The
driving roller 138 is connected to the below-mentioned display support
member driving motor (shown in FIG. 22). The image display unit 121
comprises a display device 122 and an optical system 123 for the display
device 122.

[0182]The attachment 140 is made of an elastic material such as resin and
is formed to have a C-shaped cross section similarly to the first
embodiment. Thus, also in the present embodiment as well as the first
embodiment, the wearable display unit 120 can be mechanically mounted to
the headphone arm 112 by simply grasping the headphone arm 112. Thus, it
is not necessary to prepare a dedicated attachment on the side of the
headphones. In other words, the present embodiment does not need
dedicated headphones.

[0183]The cable connection part (the external connection part) 114 of the
headphones 110 is connected with a controller 160 that controls the
headphones 110 and the wearable display unit 120. This controller 160
comprises: a controller cable 161 connected with the cable connection
part 114 of the headphones 110; an image signal receiving terminal 162
for receiving an image signal from the outside; an audio signal receiving
terminal 163 for receiving an audio signal from the outside; an operation
part 164 for user's operation; a signal storage part 165 for storing the
image signal and the audio signal; an amplifier 166 that amplifies the
audio signal; a control part 167 that sends a control signal to various
parts according to instructions from the operation part 164; and a main
power supply circuit 168. The controller cable 161 has a connector 161a
provided with electric contacts. The connector 161a is provided with: an
audio signal line S1 for sending the audio signal from the amplifier 166
to the cable connection part 114 of the headphones 110; an image signal
line I1 for sending the image signal from the signal storage part 165 and
the image signal receiving terminal 162 to the cable connection part 114
of the headphones 110; a control signal line C1 for sending the control
signal from the control part 167 to the cable connection part 114 of the
headphones 110; and a power line P1 for sending power from the main power
supply circuit 168 to the cable connection part 114 of the headphones
110.

[0184]The cable connection part 114 of the headphones 110 is provided with
a controller-side connector 115a connected to the connector 161a of the
controller cable 161 and a display-side connector (a headphone-side
electric connection part) 115b connected to a connector 139a of the
display cable 139. The controller-side connector 115a and the
display-side connector 115b are connected with each other through an
image signal line I2, a control signal line C2, a power line P2 and a
ground line (not shown). Through the connectors 161a and 115a, the image
signal line I1, the control signal line C1, the power line P1 and a
ground line provided in the controller cable 161 are connected
respectively to the image signal line I2, the control signal line C2, the
power line P2 and the ground line that are connected to the
controller-side connector 115a. Further, the audio signal line S1
provided in the controller cable 161 is connected to the speakers 111R
and 111L through the connectors 161a and 115a and the audio signal line
S2.

[0185]Within the display support member housing 136 of the wearable
display unit 120, there are provided: a display processing part 124 for
sending the image signal to the display device 122; a display support
member drive control part 125 for moving the display support member 131;
a gravity sensor 128 for detecting the up-and-down direction and for
informing the display processing part 124 of a detection result; and a
power supply circuit 129 for supplying electric power to these parts 124,
125 and 128 and to the display device 122. The display support member
drive control part 125 comprises: a display support member driving motor
126 as a driving source for moving the display support member 131; a
group of sensors 127 for detecting a forward movement critical position
and a backward movement critical position of the display support member
131. The display cable 139 comprises: an image signal line I3 connected
to the image signal line I2 of the display-side connector 115b of the
headphones 110 through the connector 139a; a control signal line C3
connected to the control signal line C2 of the display-side connector
115b through the connector 139a; a power line P3 connected to the power
line P2 of the display-side connector 115b through the connector 139a;
and a ground line not shown. The image signal line I3 of the display
cable 139 is connected to the display processing part 124 in the display
support member housing 136; the control signal line C3 of the display
cable 139 is connected to the display processing part 124 and the display
support member drive control part 125 in the display support member
housing 136; and the power line P3 of the display cable 139 is connected
to the power supply circuit 129 in the display support member housing
136. Further, the display support member 131 is provided with: an image
signal line I4 for sending the image signal from the display processing
part 124 in the display support member housing 136 to the display device
122; a power line P4 for supplying electric power from the power supply
circuit 129 in the display support member housing to the display device
122; and a ground line not shown.

[0186]Thus, in the present embodiment, not only the audio signal from the
controller 160 but also the image signal, the control signal and the
electric power are sent to the cable connection part 114 of the
headphones 110. Among these, the audio signal is sent to each speaker
111R, 111L of the headphones 110, and the image signal, the control
signal and the electric power are sent to the display support member
housing part 133 of the wearable display unit 120 through the cable
connection part 114 of the headphones 110. Namely, in the present
embodiment, all the signals and the like sent from the controller 160 to
the wearable display unit 120 and the headphones 110 are once sent to the
headphones 110 so that the number of cables extending from the controller
160 becomes smaller.

[0187]In using the wearable display unit 120 together with the headphones
110, the attachment 140 of the wearable display unit 120 is mechanically
coupled to the headphone arm 112 as described above. At that time, the
attachment 140 of the wearable display unit 120 may be fixed either to
the neighborhood of the right speaker 111R or to the neighborhood of the
left speaker 111L of the headphone arm 112. Next, the display cable 139
is connected to the display-side connector 115b of the headphones 110, to
connect the headphones 110 and the wearable display unit 120
electrically. Further, the controller cable 161 is connected to the
controller-side connector 115a of the headphones 110, to connect the
controller 160 and the headphones 110 electrically. Here, the mechanical
coupling and the electric connection of the wearable display unit 120
with the headphones 110 and the electric connection of the controller 160
with the headphones 110 can be carried out in any order.

[0188]Then, the headphones 110 with which the wearable display unit 120 is
connected mechanically and electrically is mounted on the head.

[0189]When a user wants to output sound together with a picture, the user
operates the play button and the like of the operation part 164 of the
controller 160. When the play button is pushed, the main power supply
circuit 168 outputs electric power and the control part 167 outputs the
display support member drive control signal. Then, the electric power and
the display support member drive signal are sent to the wearable display
unit 120 through the cable connection part 114 of the headphones 110. The
electric power is sent to the power supply circuit 129 of the wearable
display unit 120, and then supplied various parts in the wearable display
unit 120. On the other hand, the display support member drive signal is
sent to the display support member drive control part 125 of the wearable
display unit 120. As a result, the display support member driving motor
126 of the display support member drive control part 125 operates, and
makes the display support member 131 project from the retracted position
to the displayable position. When a group of sensors 127 of the display
support member drive control part 125 detects the forward movement
critical position (i.e. the displayable position), the control part 167
of the controller 160 is notified of this fact. Then, according to an
instruction from the control part 167, the image signal and the audio
signal stored in the signal storage part or the image signal received
through the image signal receiving terminal 162 and the audio signal
received through the audio signal receiving terminal 163 are outputted to
the cable connection part 114 of the headphones 110.

[0190]The controller 160 sends the audio signal to each speaker 111R, 111L
of the headphones to reproduce the sound corresponding to the audio
signal. Further, the controller 160 sends the image signal to the display
device 122 through the cable connection part 114 of the headphones 110
and the display processing part 124 of the wearable display unit 120, to
reproduce the image corresponding to the image signal.

[0191]In the case where the attachment 140 of the wearable display unit
120 is removed from the position in the neighborhood of the left speaker
111L of the headphone arm 112 and mechanically coupled to a position in
the neighborhood of the right speaker 11R, the wearable display unit 120
is turned upside down. However, the external shape of the wearable
display unit 120 (including the display screen of the image display unit
122) of the present embodiment is symmetrical in the vertical direction
in a state that the wearable display unit 120 is mounted horizontally on
the user's head. Thus, even if the wearable display unit 120 is turned
upside down as a result of changing its fixing position from the left to
the right, the user can use the wearable display unit 120 without feeling
uncomfortable. Further, even if the wearable display unit 120 is turned
upside down as a result of changing its fixing position from the left to
the right, the gravity sensor 128 can detect the state, and the display
processing part 124 automatically reverses the top and the bottom of a
displayed image. Thus, the top of the displayed image is displayed
correctly on the upper side. Thus, it is possible to solve inversion of
the image owing to change of the left and right fixing positions of the
wearable display unit 120.

[0192]When the headphones 110 are used by themselves, the display cable
139 of the wearable display unit 120 is removed from the cable connection
part 114 of the headphones 110 and the attachment 140 of the wearable
display unit 120 is removed from the headphone arm 112. In other words,
the mechanical and electric connections between the headphones 110 and
the wearable display unit 120 are released. Then, when the controller 160
sends the audio signal to the headphones 110, the sound corresponding to
the audio signal is reproduced through the speakers 111R and 111L of the
headphones.

[0193]As described above, in the present embodiment, the mechanical and
electric connections between the headphones 110 and the wearable display
unit 120 can be released, and thus the headphones 110 can be used by
themselves. In addition, the headphone arm 112 can be coupled
mechanically to the wearable display unit 120 without providing a special
fixing mechanism to the headphone arm 112 as a head mounting belt. As a
result, the beauty of the headphones 110 is improved even at the time of
using by themselves.

[0194]Although, in the present embodiment, the amplifier 166 is provided
in the controller 160, the amplifier 166 may be provided in the
headphones 110. In that case, wires may be provided for supplying
electric power from the controller 160 to the amplifier in the headphones
110. Further, in the present embodiment, the display processing part 124
is provided in the display support member housing part 133 of the
wearable display unit 120. However, a part of the functions of the
display processing part 124, for example a function of driving the
display device 122 may be provided in the image display unit 121. Or, all
the functions of the display processing part 124 may be provided in the
image display unit 121. Or, a part of various functional parts of the
wearable display unit 120 and a part of various functional parts of the
controller 160 may be suitably provided in other parts.

[0195]Next, will be described first and second variants of the attachment
in the first and second embodiments, referring to FIGS. 23 and 24
respectively. FIG. 23 is a cross section showing the first variant of the
attachment of the wearable display system of the second embodiment, and
FIG. 24 is a cross section showing the second variant of the attachment
of the wearable display system.

[0196]As shown in FIG. 23, the attachment 140a as the first variant
comprises: a groove member 141 having a pair of side walls 142a and 142b
opposed to each other; a second grasping member 143 that grasps the
headphone arm 112 between it and one side wall (hereinafter, referred to
as a first grasping member) 142a; and a screw member 144 as a pressing
member that presses the second grasping member 143 toward the first
grasping member 142a.

[0197]The groove member 141 is formed integrally with the clearance part
135 of the display support member housing part 133. The side wall 142a of
the groove member 141 on the side of the clearance part 135 becomes the
first grasping member. The other side wall 142b of the groove member 141
is formed with a threaded hole into which the screw member 144 as the
pressing member is screwed. The second grasping member 143 is fixed to
the tip of the screw member 144.

[0198]To couple the attachment 140a to the headphone arm 112, a part of
the headphone arm 112 is positioned between the first and second grasping
members 142a and 143. Then, the screw member 144 is screwed to narrow the
distance between the first grasping member 142a and the second grasping
member 143 so that both grasping members 142a and 143 grasp the headphone
arm 112 between them.

[0199]The attachment 140b as the second variant is shown in FIG. 24, and
different from the first variant in that the screw member 144 as the
pressing member is replaced by a spring coil 144b as an elastic member.

[0200]To couple this attachment 140b to the headphone arm 112, a space
between the first grasping member 142a and the second grasping member 143
is widened to shrink the spring coil 144b. Then, a part of the headphone
arm 112 is placed between the first and second grasping members 142a and
143 so that the elastic force of the spring coil 144b pushes the second
grasping member 143 toward the first grasping member 142b to grasp the
headphone arm 112 between the grasping members 142b and 143.

[0201]Thus, in both the first and second variants, the wearable display
unit can be coupled to the headphone arm 112 simply by grasping the
headphone arm 112. Further, in these variants, the headphone arm 112 is
grasped when the attachment 140a, 140b changes its form as a result of
movement of the second grasping member 143. Accordingly, these variants
can be adapted for a headphone arm 112 that has a slightly different
cross section.

[0202]Next, will be described a variant of the headphones 110 in the
second embodiment, referring to FIG. 25.

[0203]In headphones 110a of the present variant, the cable connection part
114 in the second embodiment is divided into three parts. In detail,
cable connection parts 114a, 114R and 114L in the present variant are a
controller cable connection part 114a to which the controller cable 161
from the controller 160 is connected, and two display cable connection
parts 114R and 114L to which the display cable 139 from the wearable
display unit 120 is connected.

[0204]The controller cable connection part 114a is provided at the same
position as the cable connection part 114 in the second embodiment,
namely at the center of the headphone arm 112. And, two display cable
connection parts 114R and 114L are each provided between the left or
right speaker 111R or 111L and the controller cable connection part 114a.
Each display cable connection part 114R, 114L has a connector to which
the connector 139a of the display cable 139 can be connected. Similarly
to the second embodiment described referring to FIG. 22, each connector
of the display cable connection parts 114R and 114L is connected with the
power line P2, the image signal line I2, the control signal line C2 and
the ground line from the connector of the controller cable connection
part 114a.

[0205]By placing the two display cable connection parts 114R and 114L in
the neighborhoods of the left and right speakers 111R and 111L
respectively, it is possible to shorten the length of the display cable
139 to be connected to these display cable connection parts 114R and
114L.

Third Embodiment

[0206]Next, referring to FIGS. 26-28, will be described a third embodiment
of the wearable display system which can be arranged near a user's eye.
FIG. 26 is a perspective view showing the wearable display system (in a
coupled state) of the third embodiment; FIG. 27 is a perspective view
showing the wearable display system (in a non-coupled state); and FIG. 28
is a circuit block diagram of the wearable display system.

[0207]As shown in FIGS. 26 and 27, the wearable display system of the
present embodiment has the basically same mechanical configuration as the
configuration of the second embodiment except that arrangement of the
power line, the signal line and the like is different.

[0208]The display support member housing 136 of the wearable display unit
120b is provided with connection parts at the end portion on the opposite
side to the insertion hole for the headphone support member 131. These
connection parts are connected with a headphone cable 119 extending from
the headphones 110b and the controller cable 161 extending from the
controller. As shown in FIG. 28, within the display support member
housing 136, are provided the display processing part 124, the display
support member drive control part 125, the gravity sensor 128 and the
power supply circuit 129 similarly to the second embodiment. The
connection part to which the controller cable 161 is connected has a
controller-side connector (an external connection part) 139c and the
connection part to which the headphone cable 119 is connected has a
headphone-side connector 139b. The controller-side connector 139c is
connected with: an image signal line I2b connected to the image signal
line I1 of the controller cable 161 through the connector 161a; a control
signal line C2b connected to the control signal line C1 of the controller
cable 161 through the connector 161a; a power line P2b connected to the
power line P1 of the controller cable 161 through the connector 161a; and
an audio signal line S2b connected to the audio signal line S1 of the
controller cable 161 through the connector 161a. Further, ground lines
not shown in the figure are connected to each other. The image signal
line I2b extending from the controller-side connector 139c is connected
with the display processing part 124. The control signal line C2b is
connected with the display processing part 124, the display support
member drive control part 125 and the gravity sensor 128. And, the power
line P2b is connected with the power supply circuit 129. Further, the
audio signal line S2b and the ground line are connected to the
headphone-side connector 139b.

[0209]The cable connection part 114b of the headphones 110b is provided
with the headphone cable 119, and a connector (a headphone-side electric
connection part) 119b of the headphone cable 119 is connected to the
headphone-side connector (a display-side electric connection part) 139b
of the wearable display unit 120b.

[0210]Namely, in the present embodiment, the image signal, the audio
signal and the electric power from the controller 160 are sent to the
wearable display unit 120b. Among these, only the audio signal is sent to
the headphones 110b through the wearable display unit 120b. The other
signal and the like are processed in the wearable display unit 120b.

[0211]As described above, in the present embodiment, all the signals and
the like sent from the controller 160 to the wearable display unit 120b
and the headphones 110b are once sent to the wearable display unit 120b.
As a result, the number of cables extending from the controller 160 is
reduced. Further, the headphones 110b of the present embodiment receives
only the audio signal from the wearable display unit 120b and uses the
headphone cable 119 for receiving the audio signal. In addition, the
headphones 110b do not need a special fixing structure for mechanical
coupling to the wearable display unit 120b. As a result, ordinary
headphones sold on the market can be used as the headphones 110b.
Further, lead wires provided in the headphone cable 119 and the headphone
arm 112 are only a right signal line, a left signal line and a ground
line. Thus, thin wires can be used as the lead wires in the headphone
cable 119 and the headphone arm 112. As a result, the headphones 110b
itself can be made smaller and lighter and uncomfortable feeling at the
time of mounting on the user's head can be reduced.

Fourth Embodiment

[0212]Next, referring to FIGS. 29-33, will be described a fourth
embodiment of the wearable display system of which the image display unit
can be arranged near a user's eye. FIG. 29 is a perspective view showing
the wearable display system (in a non-coupled state) of the fourth
embodiment; FIG. 30 is a horizontal cross section showing main parts of
the wearable display system of the fourth embodiment; FIG. 31 is a
vertical cross section showing an attachment of the wearable display
system; FIG. 32 is an explanatory view showing arrangement of electric
contacts in left and right coupling portions of the wearable display
system; and FIG. 33 is a circuit block diagram of the wearable display
system.

[0213]As shown in FIG. 29, the wearable display system of the present
embodiment also comprises headphones 110c and a wearable display unit
120c similarly to the above-described embodiments.

[0214]At an almost central portion of the headphone arm 112 of the
headphones 110c, there is provided a cable connection part 1114c to which
the controller cable 161 is connected. Further, in the neighborhoods of
the left and right speakers 111R and 111L of the headphone arm 112, there
are formed respective coupling portions 116, 116 to which the wearable
display unit 120c is coupled. Further, multiple electric contacts 116a,
116a, . . . are provided in each of these coupling portions 116, 116. On
both sides of each coupling portion 116, are formed projections 117, 117
for restricting a shift of the wearable display unit 120c in the
longitudinal direction of the headphone arm 112. The electric contacts
116a of each coupling portion 116 are formed on the outer side of the
headphone arm 112 of an arc shape adapted for a shape of a head. Further,
an anti-rotation member 116b for preventing rotation of the wearable
display unit 120c is formed on the inner side of each coupling portion.
As shown in FIG. 31, this anti-rotation member 116b projects toward the
opposite side to the electric contacts 116a and has a width corresponding
to the opening width of the attachment 140c having a C-shaped cross
section. FIG. 31 shows cross sections of a coupling portion 116 and the
attachment 140c coupled to the coupling portion 116.

[0215]As shown in FIG. 30 illustrating the cross section of the display
support member housing 136, the clearance part 135 of the display support
member housing 136 is provided with a displacement mechanism 150. The
displacement mechanism 150 is used for changing the relative position and
direction of the image display unit 121 with respect to the attachment
140. The displacement mechanism 150 comprises a ball 151 provided in the
attachment 140 and a ball socket 152 formed in the clearance part 135 of
the display support member housing 136. Frictional force larger than a
certain magnitude acts between the ball 151 and the ball socket 152.
Thus, the ball socket 152 can not rotate relatively to the ball 151
unless turning force larger than a certain magnitude acts on the ball
socket 152 in relation to the ball 151. Further, as shown in the figure,
lead wires are provided within the displacement mechanism 150.

[0216]As shown in FIGS. 30 and 31, the internal surface of the attachment
140c of the C-shaped cross section is provided with a plurality of
electric contacts 145c, 145c, that are respectively in contact with a
plurality of electric contacts 116a, 116a, . . . provided in each
coupling portion 116 of the headphone arm 112. Theses electric contacts
145c are connected with the lead wires that form the signal lines and the
power line. These lead wires pass through the insides of the attachment
140c and the ball 151 and extend toward the inside of the display support
member housing 136.

[0217]As shown in FIG. 33, wiring of the signal lines and the like in the
wearable display unit 120 and the headphones 110 is basically similar to
the wiring of the second embodiment. However, as described above, the
headphone arm 112 has a plurality of electric contacts 116a, 116a in each
of the two portions (i.e. the left and right portions) in order to
establish electric connection with the wearable display unit 120.
Accordingly, the power line P2, the control signal line C2 and the image
signal line I2 extending from the controller-side connector 115c of the
headphones 110 are each branched on the way to extend to two electric
contacts 116a, 116a. Out of two sets of electric contacts 116a, 116a
provided respectively at the two portions of the headphone arm 112, one
set of electric contacts 116a become in contact with a plurality of
electric contacts 145c provided in the attachment 140c at the time of
mechanical coupling between the attachment 140c of the wearable display
unit 120c and the headphone arm 112. The other set of electric contacts
116a are connected with terminating resistance for consuming a signal
transmitted through the image signal line I2 so that the image signal is
efficiently supplied to the display processing part 124. In fact,
considering the external appearance also, a cap having terminating
resistance is put on the other set of electric contacts 116a.

[0218]The top and the bottom of the wearable display unit 120c are
reversed between the case where the wearable display unit 120c is coupled
to the coupling portion 116 on the right side of the headphone arm 112
and the case where the wearable display unit 120c is coupled to the
coupling portion 116 on the left side of the headphone arm 112.
Accordingly, it is necessary to differentiate the arrangement of a
plurality of electric contacts 116a in the coupling portion 116 on the
right side from the arrangement of a plurality of electric contacts 116a
in the coupling portion 116 on the left side.

[0219]FIG. 32 is a view showing a state of the arrangements, seeing the
left side coupling portion 116 and the right side coupling portion 116
from respective fronts of the surfaces in which electric contacts are
arranged. As shown in the figure, it is assumed that, as a plurality of
electric contacts 116a in each coupling portion 116, there exist contacts
1-8, and that, in the left coupling portion 116, the contacts 1-4 are
placed from left to right in a row, and under this group of contacts, the
contacts 5-8 are placed from left to right. As described above, when the
coupling position is changed from left to right or vice versa, the top
and the bottom of the wearable display unit 120 are reversed and, as a
result, also a plurality of electric contacts 145c provided in the
attachment 140 are turned upside down. Accordingly, in the right coupling
portion 116, the contacts 5-8 (which are placed on the lower side in the
left coupling portion 116) are placed on the upper side and the contacts
1-4 (which are placed on the upper side in the left coupling portion 116)
are placed on the lower side. Further, in the right coupling portion 116,
the contacts 1-4 are placed from right to left, i.e. to the direction to
which the headphone arm 112 extends, and the contacts 5-8 are placed from
right to left also.

[0220]In other words, as for contacts positioned side by side in a nearly
vertical direction in a state that the headphones 110c are mounted on a
user's head, their positional relationship in the vertical direction is
reversed between the left and right coupling portions 116, 116. And, as
for contacts positioned side by side in a nearly horizontal direction in
a state that the headphones 110c are mounted on the user's head, their
positional relationship in the horizontal direction is reversed between
the left and right coupling portions 116, 116.

[0221]As described above, in the present embodiment also, it is possible
to release the mechanical and electric connections between the headphones
110c and the wearable display unit 120 similarly to the above-described
embodiments. Thus, the headphones 110c can be used by themselves.
Further, since the electric contacts 116a, 145c are provided in the
headphones 110c and the mechanical attachment 140c for electrically
connecting the headphones 110c and the wearable display unit 120c, cables
for electrically connecting the headphones 110c and the wearable display
unit 120c are not required. Thus, the external appearance is improved.

[0222]In the second embodiment, the gravity sensor 128 can detect vertical
inversion of the image display unit 121 caused by a change of the
position of coupling the wearable display unit 120. In the present
embodiment, instead, it is possible to provide a sensor that detects a
state of an electrical connection of at least one contact among a
plurality of electric contacts in the attachment 120c of the wearable
display unit 120 or at least one contact among a plurality of electric
contacts in the left and right coupling portions 116. Output of this
sensor is sent to the display processing part 124, similarly to the
output of the gravity sensor 128 in the second embodiment. Based on the
output of this sensor, the display processing part 124 can recognize
whether the wearable display unit 120c is coupled on the right side or
the left side and reverse the top and the bottom of the image.

[0223]Instead of the mechanical attachment 140c of the present embodiment,
the attachment 140a or 140b of the first or second variant in the second
embodiment may be used while providing electric contacts to the
attachment 140a or 140b. This can produce similar effects, of course.

[0224]Next, referring to FIG. 34, will be described a variant of the
displacement mechanism 150 in the above-described fourth embodiment.

[0225]A displacement mechanism 150a of this variant uses a flexible wire
153 instead of the ball 151 in the displacement mechanism 150 of the
fourth embodiment. This flexible wire 153 is obtained by weaving fine
wires into a wire rod of a certain thickness and filling resin into gaps
between the fine wires and around the rod of the certain thickness. Thus,
the flexible wire 153 is deformed under a force of a certain intensity
and keeps the deformed state unless a force of a certain intensity is
applied again.

[0226]One end of this flexible wire 153 is fixed to the clearance part 135
of the display support member housing 136, and the other end to the
attachment 140c. Thus, using this flexible wire 153 instead of the ball
151 in the fourth embodiment and deforming the flexible wire 153 in
various directions, the holding part 130 and the image display unit 121
held by the holding part 130 can be displaced around each of three
independent axes in the three-dimensional space, similarly to the fourth
embodiment.

[0227]The displacement mechanism 150 of the fourth embodiment or the
displacement mechanism 150a of the present variant can be used in each of
the above- and below-described embodiments.

Fifth Embodiment

[0228]Next, referring to FIGS. 35 and 36, will be described a fifth
embodiment of the wearable display system of which the image display unit
can be arrange near a user's eye. FIG. 35 is a perspective view showing
the wearable display system of the fifth embodiment, and FIG. 36 is a
circuit block diagram of the wearable display system.

[0229]As shown in FIG. 35, also the wearable display system of the present
embodiment comprises headphones 110d and a wearable display unit 120d
similarly to the above-described embodiments.

[0230]In the neighborhoods of the left and right speakers 111R and 111L of
the headphone arm 112 of the headphones 110d, are formed respective
coupling portions 116, 116 to which the wearable display unit 120d is to
be coupled. These coupling portions 116, 116 are each provided with a
plurality of electric contacts 116d. On both sides of each coupling
portion 116, are formed projections 117, 117 for restricting a shift of
the wearable display unit 120d in the longitudinal direction of the
headphone arm 112. The electric contacts 116d of each coupling portion
116 are formed on the outer side of the headphone arm 112 of an arch
shape adapted for a shape of a head. And, on the inner side of the
headphone arm 112, is formed an anti-rotation member 116b for preventing
rotation of the wearable display unit 120d.

[0231]On the other hand, an attachment 140d of the wearable display unit
120 is coupled to a coupling portion 116 of the headphones 110d. The
attachment 140d is basically similar to the attachment of the fourth
embodiment, and the internal surface of the attachment 140d is provided
with a plurality of electric contacts that are in contact with a
plurality of electric contacts 116d, 116d provided in each coupling
portion 116 of the headphone arm 112. These electric contacts are
connected with lead wires that form the signal lines and the power line.
These lead wires pass through the inside of the attachment 140d and
extend toward the inside of the display support member housing 136. The
width (i.e. the length in the direction of the extension of the headphone
arm 112) W2 of this attachment 140d is shorter than the width W1 of each
coupling portion 116 of the headphone arm 112. As a result, the
attachment 140d can move relatively to each coupling portion 116 of the
headphone arm 112 by the length (W1-W2) in the direction of the extension
of the headphone arm 112. Accordingly, to ensure electric connections
between the electric contacts 116d of each coupling portion 116 and the
electric contacts in the attachment 140d, each electric contact 116d in
the coupling portions 116 has the length larger than (W1-W2) in the
direction of the extension of the headphone arm. In the present
embodiment also, as for contacts positioned side by side in a nearly
horizontal direction in a state that the headphones 110d are mounted on a
user's head, their positional relationship in the horizontal direction is
reversed between the left and right coupling portions 116, 116.

[0232]As shown in FIG. 36, wiring of the signal lines and the like in the
wearable display unit 120c and the headphones 110c is basically similar
to the wiring of the third embodiment. However, as described above, the
headphone arm 112 has a plurality of electric contacts 116d, 116d in each
of the two portions (i.e. the left and right portions) in order to
establish electric connection with the wearable display unit 120d.
Accordingly, the audio signal line S3b extending from each speaker 111R,
111L of the headphones 110d are branched on the way to extend to two
electric contacts 116d, 116d. Out of two sets of electric contacts 116d,
116d provided respectively at the two portions of the headphone arm 112,
one set of electric contacts 116d become in contact with a plurality of
electric contacts 145d provided in the attachment 140d at the time of
mechanical coupling between the attachment 140d of the wearable display
unit 120d and the headphone arm 112.

[0233]As described above, the present embodiment can obtain basically same
effects as ones obtained by the fourth embodiment. Further, in the
present embodiment, the wearable display unit 120d can be moved
relatively to the headphones 110 in the direction in which the headphone
arm 112 extends. As a result, it is possible to have a larger degree of
freedom of displacement of the wearable display unit 120d in relation to
the headphones 110d, in comparison with the fourth embodiment.

Sixth Embodiment

[0234]Next, referring to FIGS. 37-39, will be described a sixth embodiment
of the wearable display system of which the image display unit can be
arranged near a user's eye. FIG. 37 is a perspective view showing the
wearable display system of the sixth embodiment; FIG. 38 is a cross
section showing a speaker, an attachment and a displacement mechanism of
the wearable display system; and FIG. 39 is a cross section showing a
speaker and an outer cap of the wearable display system.

[0235]As shown in FIG. 37, the wearable display system of the present
embodiment comprises headphones 110e and a wearable display unit 120e,
similarly to the above-described embodiments.

[0236]The wearable display system of the present embodiment has the
basically same circuit configuration, wiring of the signal lines and the
like as those of the wearable display system of the fifth embodiment
described referring to FIG. 36. However, as described in the following,
the present embodiment is different from the above-described embodiments
in that the wearable display unit 120e is coupled to a speaker 111 of the
headphones 110e. As a result, positions of electric contacts for
electrically connecting the headphones 110 and the wearable display unit
120e are different from ones in the fourth embodiment.

[0237]A coupling portion 118, to which the wearable display unit 120e is
to be coupled, is formed in each of left and right speakers 111R and 111L
of the headphones 110e on the side opposite to the side contacting with a
user's head. As shown in FIG. 38, this coupling portion 118 is formed
with a collar 118a projecting toward the inner side at an opening edge of
a groove. This collar 118a is formed with elastic resin and can be
deformed. In a portion corresponding to the bottom of the groove of each
coupling portion 118, there are provided a plurality of electric contacts
116d, 116d, . . . for receiving the audio signal.

[0238]The wearable display unit 120e comprises: an image display unit 121
for displaying an image in front of a user's eye; an attachment 140e that
can be coupled to the coupling portion 118 of each speaker 111R, 111L;
and a holding part 130 that connects the image display unit 121 to the
attachment 140e.

[0239]As shown in FIG. 38, the attachment 140e has a shape that can be
inserted into the coupling portion 118 of a speaker 111. In detail, the
attachment 140e comprises: an attachment main body 141e of a hollow
cylinder shape; and a coupling collar 142e that enters between the bottom
of a coupling portion 118 and the collar 118a of the coupling portion
118. The coupling collar 142e is provided on the outer periphery of the
bottom 143e of the attachment main body 141e. To couple the attachment
140e to a speaker 111, the collar 118a of the coupling portion 118 of the
speaker 111 is deformed elastically, to insert the coupling collar 142e
of the attachment 140e between the bottom of the coupling portion 118 and
its collar 118a. The bottom 143e of the attachment main body 140e is
provided with electric contacts 145d that are to be connected to the
electric contacts 116d of a speaker 111. When the attachment 140e has
been coupled to the coupling portion 118 of a speaker 111, these electric
contacts 145d are electrically connected to the electric contacts 116d of
the coupling portion 118.

[0240]As described above, the wearable display system of the present
embodiment has the basically same circuit configuration, wiring of the
signal lines and the like as those of the fifth embodiment. However, the
present embodiment is different from the fifth embodiment in that a part
of the circuit configuration provided in the display support member
housing 136 is placed inside the hollow attachment main body 141e.
Further, a circuit board formed with such circuits is connected with the
controller cable 161 extending from the controller 160. The
above-mentioned electric contacts 145d of the attachment 140e are
connected, through the circuit board 143, with the audio signal line
included in the controller cable 161. Further, the control signal lines,
the image signal line, the power line and the like extend from each
circuit 124, 129 or the like on the circuit board 143. The control signal
lines are connected to the display support member drive control part 125
and the like provided in the display support member housing 136 of the
holding part 130. The image signal line is connected to the image display
unit 121. And, the power line supplies electric power to the display
support member drive control part 125 and the image display unit 121.

[0241]A displacement mechanism 150e for changing the directions and
positions of the holding part 130 and the image display unit 121
relatively to the attachment 140e is provided between the display support
member housing 136 and the attachment 140e. The displacement mechanism
150e comprises: an up-and-down movement rotation axis member 151e for
moving the image display unit 121 up and down; and a left-and-right
movement rotation axis member 154e for moving the image display unit 121
to the left and to the right. The up-and-down movement rotation axis
member 151e comprises: an axis member 152e that is fixed to the
attachment 140e on the opposite side to the electric contacts 145d; and a
bracket member 153e that extends from the axis member 152e toward the
holding part 130. The left-and-right movement rotation axis member 154e
passes through the bracket member 153e of the up-and-down movement
rotation axis member 151e and a bracket member 136e of the display
support member housing 136. In the displacement mechanism 150e,
frictional force larger than a certain magnitude acts between the axial
parts and the socket parts, and thus a socket part does not rotate
relatively to an axial part unless a force larger than a certain level is
applied from the side of the display support member housing 136.

[0242]In the present embodiment, each of the right speaker 111R and the
left speaker 111L is formed with a coupling portion 118. Thus, when the
wearable display unit 120e is coupled to the right speaker 111R for
example, the coupling portion 118 of the left speaker 111L is exposed.
This is not favorable from the viewpoint of the external appearance.
Thus, the present embodiment has an outer cap 140f for covering the
coupling portion 118 of a speaker 111 to which the wearable display unit
120e is not coupled. As shown in FIG. 39, the outer cap 140f is similar
to the attachment 140e in their external appearances, and has a collar
142f that is fit into the coupling portion 118 of each speaker 111.
Further, the outer cap 140f is hollow similarly to the attachment 140e,
and a division plate 143f similar to the circuit board 143 of the
attachment 140e is provided inside the outer cap 140f. The division plate
143f is provided in order to form the same space Sf within the outer cap
140f as a space Se formed between the circuit board 143 and the bottom
143e of the attachment main body 141e as a result of providing the
circuit board 143 in the attachment 140e. Owing to this arrangement, it
is possible to obtain the same sound quality both from the left speaker
111L and the right speaker 111R.

[0243]As described above, also in the present embodiment, all the signals
and the like sent from the controller 160 to the wearable display unit
120e and the headphones 110e are once sent to the wearable display unit
120e similarly to the third and fifth embodiments. As a result, the
number of cables extending from the controller 160 can be reduced.
Further, it is not necessary to provide the image signal line in the
headphones. This reduces the weight of the headphones. Further, the outer
cap 140f can consume the image signal, it is not necessary to provide a
terminating resistance separately.

[0244]In the present embodiment, all the signals and the like sent from
the controller 160 to the wearable display unit 120e and the headphones
110 are once sent to the wearable display unit 120e. However, similarly
to the second and fifth embodiments, it is possible that all the signals
and the like sent from the controller 160 to the wearable display unit
120 and the headphones 110e are once sent to the headphones 110e, and the
wearable display unit 120e receives the image signal and electric power
from the headphones 110.

[0245]Further, in the present embodiment, the attachment 140e is coupled
to a speaker 111 by deformation of an elastic body. However, as shown in
FIG. 40, for example a magnet 149 may be provided to either of the
attachment 140e and a speaker 111, and a magnetic body such as iron may
be provided to the other so that the attachment 140e is attached to the
speaker 111.

[0246]Further, in the case where a plurality of electric contacts exist as
the electric contacts 116d of the coupling portion 118 of each speaker
111, it is favorable that these contacts are arranged as described above
referring to FIG. 32.

[0247]Further, into the present embodiment, may be combined various
structures of the above-described embodiment and their variants such as
the various constructions of the display support member and its support
forms described in the first embodiment, the circuit configuration of the
system described in the second embodiment or the like, and the
constructions of the auxiliary holding parts that will be described in
the seventh embodiment.

Seventh Embodiment

[0248]Referring to FIGS. 41-44, will be described a seventh embodiment of
the wearable display system of which the image display unit can be
arranged near a user's eye.

[0249]FIG. 41 is a perspective view showing an external appearance of the
wearable display system in the case where the wearable display system is
mounted on a head H of a user U. In the present embodiment, the head H
includes the neck of the user U who uses the wearable display system, and
thus refers to the neck and a part above the neck.

[0250]The wearable display system of the present embodiment comprises:
headphones 210 that is to be mounted on a head H and has functions of
generating sound such as voice, music, sound effects and the like; and a
wearable display unit 220 that has a function of displaying an image for
a user U. Further, the wearable display unit 220 is connected with a
cable 230. The cable 230 supplies electric power and sound/image signals
from a power supply unit (not shown) and a sound/image signal generation
unit (not shown) to the wearable display system.

[0251]The headphones 210 comprise: a right speaker 211a; a left speaker
211b; a right earpiece 212a; a left earpiece 212b; and a headphone arm
213 that connects the right and left speakers 211a and 211b.

[0252]The right speaker 211a and the left speaker 211b have a sound output
function, and a sound signal from the cable 230 is supplied to these
speakers 211a and 211b.

[0253]The right earpiece 212a is connected to the right speaker 211a and
assists the right speaker 211a to be mounted on and in close contact with
the head H. Further, the left earpiece 212b is connected to the left
speaker 211b and assists the left speaker 211b to be mounted on and in
close contact with the head H.

[0254]The headphone arm 213 holds the head H of the user U inside the
headphone arm 213 by its elastic force and connects the right speaker
211a and the left speaker 211b with each other.

[0255]The wearable display unit 220 comprises: a image display unit 222; a
holding part 221 that can hold the image display unit 222 in front of an
eye of the user U; an attachment 227 that connects the holding part 221
and the headphone arm 213; an auxiliary holding part 240 provided to the
holding part 221; a head pressing detection sensor 250 provided in the
auxiliary holding part 240.

[0256]The auxiliary holding part 240 is provided to the holding part 221
at a position where the auxiliary holding part 240 does not enter the
field of vision of the user U in a state that the center of the field of
vision of the user U coincides with the center of an image on the image
display unit 222.

[0257]The image display unit 222 reproduces and displays the image signal
sent through the cable 230. The known techniques can be used for
reproduction and display of the image signal.

[0258]The holding part 221 comprises: a connection part 223; a display
support member 224; and a display support member housing part 225.

[0259]The connection part 223 connects the image display unit 222 and the
display support member 224. The connection part 223 may use a ball joint
so that the direction of displaying an image on the image display unit
222 can be changed continuously centering on the connection part 223.

[0260]One end of the display support member 224 is connected to the image
display unit 222 through the connection part 223. The other end of the
display support member 224 is slidably held by the display support member
housing part 225. Further, as shown in FIG. 42, the display support
member 224 is provided with a holding member 224a, a pin 224b and a
spring fixing member 224c in the surface that faces the head H. FIG. 42
is a cross section showing main parts of the wearable display system.

[0261]The display support member 224 is a pipe-shaped arm and draws a
curve running along a curve extending from the temporal part of the head
H to the face part. The display support member 224 has strength that
bears the weight of the image display unit 222 and the connection part
223.

[0262]The display support member housing part 225 houses at least a part
of the display support member 224 as well as at least a part of the
auxiliary holding part 240 in its inside.

[0263]In the present embodiment, when the image display unit 222 is
retracted from the front of an eye of the user U and at least a part of
the display support member is housed in the display support member
housing part 225 as shown in FIG. 42, it is said that the display support
member 224 is in a housed position. Further, when the display support
member 224 supports the image display unit 222 in front of a user's eye
(FIG. 41), it is said that the display support member 224 is in a
projecting position.

[0264]The display support member housing part 225 comprises: a display
support member housing 226; a display support member position detection
sensor 231; a holding part driving unit 232; a control unit 235; and a
mode selection switch 236.

[0265]A housing space 226a inside the display support member housing 226
has sufficient size for housing the display support member 224 and the
auxiliary holding part 240 positioned along the display support member
224. Further, the housing space 226a has depth for housing at least a
part of the display support member 224.

[0266]The display support member position detection sensor 231 is a
pressure sensor. Instead of this sensor 231, the sensors of the first
embodiment may be used. A fixing location of the display support member
position detection sensor 231 is the innermost portion of the housing
space 226a. In the present embodiment, when the display support member
224 is positioned at the housed position, one end 224d of the display
support member 224 at which the image display unit 222 is not fixed
presses the innermost portion of the housing space 226. As a result, the
display support member position detection sensor 231 detects the pressure
from the display support member 224, and thus detects that the display
support member 224 is at the housed position.

[0267]The holding part driving unit 232 comprises: a display support
member driving motor (not shown); a power line (not shown) and a control
line (not shown) connected to the display support member driving motor; a
motor shaft 233; and a driving roller 234 fixed to the motor shaft 233.
An outer periphery of the driving roller 234 is in contact with an inner
side surface of the curved display support member 224. The driving roller
234 can move the display support member 224 slidingly by the turning
force given from the electric motor to the motor shaft 233.

[0268]As shown in FIG. 42, the mode selection switch 236 is partly
projecting outside the display support member housing 226, and thus it is
possible to operate the mode selection switch 236 while using the display
support member housing 226. The mode selection switch 236 switches
between three modes, i.e. a manual mode in which sliding operation of the
display support member 224 is carried out manually, an electric operation
mode in which the holding part driving unit 232 is activated
electrically, and an off mode in which the switch is turned off. In the
cases of the electric operation mode and the manual mode, a stopper for
stopping rotation of the driving roller 234 is released.

[0269]FIG. 43 is a cross section showing a part of the display support
member 224, the auxiliary holding part 240 and the head pressing
detection sensor 250.

[0270]The auxiliary holding part 240 comprises: a pressing member 401 that
presses the head H at a pressure larger than a certain value; a shaft
member 402; a spring fixing member 403; and a mounting member 405 for
mounting the shaft member 402 to the display support member 224. The
pressing member 401 is provided with the head pressing detection sensor
250. Further, a movement sensor 407 for detecting a change in movement of
the head H is provided within the pressing member 401.

[0271]The pressing member 401 has a spherical shape and is connected to
the shaft member 402. Further, the pressing member 401 presses the head
H.

[0272]The shaft member 402 is swingably mounted to the display support
member 224 by means of the holding member 224a and the pin 224b through
the mounting member 405.

[0273]A pressing force generation unit 245 generates a pressing force of
the auxiliary holding part 240, and comprises electromagnets 451 and 452
and a spring 453. The electromagnet 452 is fixed to the shaft member 402,
and the electromagnet 451 is fixed to the display support member 224 to
face the electromagnet 452. The electromagnets 451 and 452 are supplied
with electric power from the display support member housing part 225
through power lines not shown. Further, directions and strengths of
electric currents to the electromagnets 451 and 452 can be controlled by
the control unit 235 (FIG. 44: described below) in the display support
member housing part 225. Thus, it is possible to control electromagnetic
forces such that the electromagnets 451 and 452 attract or repel each
other.

[0274]One end of the spring 453 is fixed to the spring fixing member 224c
on the display support member 224. The other end of the spring 453 is
fixed to the spring fixing member 403 on the shaft member 402. When the
pressing member 401 swings in the direction of moving toward the display
support member 224 (i.e. the direction of the arrow B) around the pin
224b as the rotation axis, the spring 453 exercise its elastic force in
the direction of canceling the swinging (i.e. the direction of the arrow
A).

[0275]The movement sensor 407 provided within the pressing member 401
comprises a gyro sensor. The movement sensor 407 detects a change in
movement of the head H in a state that the pressing member 401 presses
against the head H.

[0276]The head pressing detection sensor 250 is mounted on the surface of
the pressing member 401 at a portion that presses against the head H.

[0277]Output of the movement sensor 407 and output of the head pressing
detection sensor 250 are sent to the control unit 235 provided in the
display support member housing part 225 through respective signal lines
(FIG. 44).

[0278]In the present embodiment, when the pressing member 401 of the
auxiliary holding part 240 is at a position where the pressing member 401
can press against the head H, that position is referred to as a pressing
position of the auxiliary holding part 240. Further, when the pressing
member 401 of the auxiliary holding part 240 is at a position where the
pressing member 401 can not press against the head H, that position is
referred to as a retracted position of the auxiliary holding part 240.
The auxiliary holding part 240 is provided in such a manner that the
auxiliary holding part 240 can swing between the pressing position and
the retracted position.

[0279]FIG. 44 is a circuit block diagram relating to driving/control of
the wearable display system.

[0280]The control unit 235 is connected with the display support member
position detection sensor 231, the holding part driving unit 232 and the
mode selection switch 236 provided in the display support member housing
part 225, the movement sensor 407 and the pressing force generation unit
245 placed in the auxiliary holding part 240, the head pressing detection
sensor 250, and the image display unit 222, through respective signal
lines. The control unit 235 sends and receives signals through those
signal lines. Further, based on the output S1 of the head pressing
detection sensor 250, the control unit 235 controls the pressing force
generation unit 245 such that the pressing level stays within a
predetermined range. Further, based on the output S3 of the display
support member position detection sensor 231, the control unit 235
controls the display support member driving motor of the holding part
driving unit 232 such that the display support member 224 is positioned
at the projecting position or the housed position.

[0281]Control and operation from the start of using the wearable display
system and to the end of using will be described in order. In the
following description, control signals between blocks will not be
mentioned and only data from each sensor will be mentioned.

[0282](1) The user U mounts the wearable display system of the present
embodiment on his head H.

[0283](2) The user U selects either the electric operation mode or the
manual mode, using the mode selection switch 236.

[0284]When the electric operation mode is selected, (3) the control unit
235 controls the holding part driving unit 232 to drive the display
support member 224 from the housed position to the projecting position.
As a result, the image display unit 222 is held in front of an eye.

[0285]When the manual mode is selected, (4) the control unit 235 releases
the stopper for the display support member 224. Here, the stopper is
provided in the holding part driving unit 232. (5) Then, the user
manually pulls the display support member 224 from the housed position to
the projecting position.

[0286]Parallel with the above step (3) or the steps (4) and (5), the
following steps (6)-(7) are performed

[0287](6) The display support member position detection sensor 231 detects
that the end 224d of the display support member 224 leaves the innermost
portion of the display support member housing part 225, and sends a
display support member position detection signal S3 to the control unit
235. (7) The control unit 235 receives the display support member
position detection signal S3 and controls the pressing force generation
unit 245 to displace the auxiliary holding part 240 from the retracted
position to the pressing position.

[0288]Further, the following control/operation is performed.

[0289](8) The control unit 235 activates the head pressing detection
sensor 250. (9) The control unit 235 activates the movement sensor 407.
(10) The pressing member 401 of the auxiliary holding part 240 presses
against the temporal part of the head H. (11) The head pressing detection
sensor 250 detects the pressing level, and sends a head pressing
detection signal S1 to the control unit 235. (12) The control unit 235
receives the head pressing detection signal S1. When the pressing level
is in the predetermined range, the control unit 235 makes the image
display unit 222 display an image. (13) Further, the control unit 235
controls the pressing force generation unit 245 such that the level of
the pressing force is maintained within the predetermined range. In
detail, the control unit 235 controls electric currents to the pressing
force generation unit 245 to adjust the electromagnetic forces of the
electromagnets 451 and 452.

[0290]When the user intends to end viewing of the image, operation/control
of the wearable display system becomes as follows.

[0291](14) When the user U returns the mode selection switch to the
position of the off mode, the control unit 235 makes the image display
unit 222 stop displaying the image. (15) The control unit 235 drives the
pressing force generation unit 245 so that the auxiliary holding part 240
moves from the pressing position to the retracted position. (16) In the
case where the user U has used the electric operation mode, the control
unit 235 drives the holding part driving unit 232 so that the display
support member 224 moves from the projecting position to the housed
position. In the case where the user U has used the manual mode, the user
U manually moves the display support member 224 into the display support
member housing part 225. At that time, also the auxiliary holding part
240 is housed in the display support member housing part 240.

[0292]It is possible to consider that the control unit 235 uses a movement
detection signal S2 of the movement sensor 407 to control the pressing
force generation unit 245. For example, based on the movement detection
signal S2 from the movement sensor 407, the control unit 235 calculates a
change in movement of the head H. Then, according to the calculated
change, the control unit 235 may control the pressing force generation
unit 245 such that the pressing level of the pressing member 402 remains
within the predetermined range. Further, switching between the retracted
position and the pressing position of the auxiliary holding part 240 may
be carried out manually. In that case, the manual operation is carried
out in a state that the mode selection switch 236 is at the manual mode.
Further, in the pressing force generation unit 245, one of the
electromagnets 451 and 452 may be a magnetic body such as iron. To put
the auxiliary holding part 240 at the pressing position, the
electromagnetic force may be turned off and only the elastic force of the
spring 453 may be used. To put the auxiliary holding part 240 at the
retracted position, it is sufficient to control the electromagnetic
forces of the electromagnet such that the electromagnetic force larger
than the elastic force attracts the magnetic body. Further, a lock
mechanism may be provided for keeping the retracted position.

[0293]As shown in FIG. 41, in the wearable display unit 220 of the present
embodiment, the auxiliary holding part 240 is provided to the display
support member 224 on the side of the display support member housing part
225 at the position where the auxiliary holding part 240 exists outside
the field of vision of the user U when the user U views the image on the
image display unit 222. Thus, the auxiliary holding part 240 rarely
interrupts the field of vision of the user U to an uncomfortable degree.
Thus, the wearable display system of the present embodiment does not
spoil visibility of surroundings.

[0294]The auxiliary holding part 240, the pressing force generation unit
245 and structure of members required for operations and the like of
these components of the present embodiment may be employed in the first
through sixth and eighth through eleventh embodiments.

Eighth Embodiment

[0295]Referring to FIGS. 45 and 46, will be described a wearable display
system of which the image display unit can be arranged near a user's eye
according to the eighth embodiment.

[0296]As shown in FIG. 45, in the present embodiment, an auxiliary holding
part 240 similar to the one of the seventh embodiment is provided not on
the display support member 224 but on the display support member housing
part 225. Accordingly, the holding member 224a, the pint 224b and the
spring fixing member 224c are provided not on the display support member
224 but on the display support member housing part 225. Further, the
electromagnet 451 of the pressing force generation unit 245 is placed on
the display support member housing part 225. Also, one end of the spring
453 is fixed to the display support member housing part 225. The other
structures are common to the seventh embodiment. Thus, the same reference
numbers are given to the common components. Further, repeated description
with respect to the common components and their operation and control
will be omitted. FIG. 45 shows a state that the display support member
224 is in the projecting position and the auxiliary holding part 240
provided swingably on the display support member housing part 225 is in
the pressing position where the auxiliary holding part 240 presses
against the temporal part.

[0297]To mount the wearable display system, the following operation will
be carried out. (1) Depending on the mode selected by the user U using
the mode selection switch 236, the display support member 224 is driven
to the projecting position manually or by the holding part driving unit
232 (the arrow A). (2) In that process, the pressing force generation
unit 245 operates according to control similar to the control in the
seventh embodiment. (3) The auxiliary holding part 240 is positioned at
the pressing position where the pressing member 401 presses against the
temporal part of the head H (the arrow B).

[0298]FIG. 46 is a perspective view showing the external appearance of the
wearable display system of the present embodiment in a state that the
display support member 224 is at the housed position. The auxiliary
holding part 240 provided on the display support member housing part 225
is at the retracted position.

[0299]To dismount the wearable display system, the following operation
will be carried out. (1) Depending on the mode selected by the user U
using the mode selection switch 236, the display support member 224 is
housed to the housed position manually or by the holding part driving
unit 232 (the arrow C). (2) In the process of housing the display support
member 224, the pressing force generation unit 245 operates according to
control similar to the control in the seventh embodiment. (3) The
auxiliary holding part 240 is positioned at the retracted position (the
arrow D).

[0300]In the present embodiment, the auxiliary holding part 240 presses
against the temporal part of the head H. However, it may be arrange such
that the auxiliary holding part 240 presses against the left speaker
211b. Further, similarly to the first embodiment, a change in movement of
the head H may be detected by the movement sensor 407. Then, pressing by
the auxiliary holding part 240 may be controlled depending on the change
in movement of the head H. Further, similarly to the seventh embodiment,
switching between the retracted position and the pressing position of the
auxiliary holding part 240 may be carried out manually. In that case,
this operation may be carried out under the manual mode selected by the
mode selection switch 236.

[0301]According to the eighth embodiment, the auxiliary holding part 240
provided on the display support member housing part 225 presses against
the temporal part of the head. As a result, the auxiliary holding part
240 is positioned outside the field of vision of the user U, and the
auxiliary holding part 240 scarcely enters the field of vision of the
user U viewing the image. Thus, the wearable display unit 220 of the
present embodiment can suppress movement of the image display unit 222
and improves visibility of surroundings.

Ninth Embodiment

[0302]A wearable display system, the image display unit of which can be
arranged near a user's eye, of a ninth embodiment will be described
referring to FIGS. 47 and 48.

[0303]As shown in FIG. 47, in the present embodiment, an auxiliary holding
part 241 having a new mechanism is provided on the display support member
housing part 225. Further, the auxiliary holding part 241 is in a
pressing position where the auxiliary holding part 241 can press, before
mounting the wearable display system on the head. The other features of
the present embodiment are common to the second embodiment. Accordingly,
the same reference numbers are given to the common components. Further,
repeated description with respect to the common components and their
operation will be omitted. FIG. 47 shows a state that the display support
member 224 is at the projecting position and the auxiliary holding part
241 provided on the display support member housing part 225 is at the
pressing position.

[0304]FIG. 48 is a cross section showing the auxiliary holding part 241 at
the pressing position and a part of the display support member housing
part 225.

[0305]The auxiliary holding part 241 comprises: a disk-shaped pressing
member 411; and a cylinder 412 that is connected to the pressing member
411 at one end and has a cylinder-shaped hollow portion 413. Further, an
open end of the cylinder 412 is slidably inserted into a hole that is
provided in the display support member housing part 225 and has a
diameter nearly same as the diameter of the cylinder 412. Further, the
auxiliary holding part 241 has a pressing force generation unit 245a.

[0306]The pressing force generation unit 245a has a spring 453. The spring
453 has a diameter nearly same as the diameter of the hollow portion 413.
One end of the spring 453 is fixed to the spring fixing portion 414 of
the auxiliary holding part 241. The other end of the spring 453 is fixed
to a spring fixing portion 258 provided in the bottom of the hole of the
display support member housing part 225.

[0307]Elastic force of the spring 453 applied to the spring fixing portion
414 of the auxiliary holding part 241 is adjusted such that the auxiliary
holding part 241 can keep the pressing position irrespective of a posture
of the wearable display system.

[0308]Operation/control of the wearable display system (FIG. 47) are
almost similar to those of the eighth embodiment except that the
auxiliary holding part 241 is at the pressing position already before
mounting the wearable display system on the head. Namely, the user U
mounts the wearable display system on his head H while his head H is
pressing back the auxiliary holding part 241 positioned at the pressing
position. Mounting operation after that is similar to the operation in
the eighth embodiment except that the auxiliary holding part 241 is
always at the pressing position where the auxiliary holding part 241 can
press.

[0309]Here, it is possible to consider such an arrangement that an
electromagnet is provided on the bottom of the hole (FIG. 48) in the
display support member housing part 225 and a magnetic body such as iron
is provided at a part of the pressing member 411. In this arrangement, to
place the auxiliary holding part 241 at the retracted position, the
electromagnetic force attracts the pressing member 411 to the
electromagnet in the bottom of the hole against the elastic force of the
spring 453. Further, at least a part of the auxiliary holding part 241
may be housed in the hole in the display support member housing part 225.
Further, to place the auxiliary holding part 241 at the pressing
position, it is sufficient to turn off the electromagnetic force of the
electromagnet so that only the elastic force of the spring 453 makes the
auxiliary holding part 241 project.

[0310]In the ninth embodiment, similarly to the eighth embodiment, the
auxiliary holding part 241 provided on the display support member housing
part 225 presses against the temporal part of the head. As a result, the
auxiliary holding part 241 is positioned outside the field of vision of
the user U, and the auxiliary holding part 241 scarcely enters the field
of vision of the user U viewing the image. Thus, according to the
wearable display unit of the present embodiment, it is possible to
suppress movement of the image display unit 222 and to improve visibility
of surroundings.

[0311]FIG. 49 shows a first variant of the ninth embodiment. In this first
variant, an attachment 227 connects the display support member housing
part 225 not to the headphone arm 213 but to the left speaker 211b. The
other components and their operations are similar to the ones in the
ninth embodiment. Fixing structure of this attachment 227 to the speaker
211b may be the above-described structure shown in FIG. 39.

[0312]According to the first variant, the display support member housing
part 225 is connected to the left speaker 211b, and thus the auxiliary
holding part 241 scarcely enters the field of vision of the user U
viewing the image. Thus, according to the wearable display unit of the
present variant, it is possible to suppress movement of the image display
unit 222 and to improve visibility of surroundings.

[0313]FIG. 50 shows a second variant of the ninth embodiment. In this
second variant, the auxiliary holding part 241 presses against not the
head H but the left speaker 211b. The other components and their
operations are similar to the one in the ninth embodiment.

[0314]According to the second variant, the auxiliary holding part 241
presses against the head H through the left speaker 211b. As a result,
the auxiliary holding part 241 scarcely enters the field of vision of the
user U viewing the image. Thus, according to the wearable display unit of
the present variant, it is possible to movement of the image display unit
222 and to improve visibility of surroundings.

Tenth Embodiment

[0315]A tenth embodiment of a wearable display system of which the image
display unit can be arranged near a user's eye will be described
referring to FIGS. 51-54. FIG. 51 is a perspective view showing the
wearable display system of the present embodiment; FIG. 52 is a cutaway
plan view showing main parts of the wearable display system; FIG. 53 is a
cross section taken along the A-A line in FIG. 52.

[0316]As shown in FIG. 51, also the wearable display system of the present
embodiment comprises: headphones 210a and a wearable display unit 220a
similarly to the above-described embodiments.

[0317]The headphones 210a comprises: a right speaker 211a; a left speaker
211b; and a headphone arm 213a that connects the right speaker 211a and
the left speaker 211b with each other. Differently from the
above-described embodiments, the headphone arm 213a is curved in the
respective neighborhoods of the speakers 211a and 211b, and these curved
portions form earpieces 214.

[0318]Further, similarly to the above-described embodiments, the wearable
display unit 220a comprises: an image display unit 222; a holding part
221; an attachment 227; and an auxiliary holding part 240a. As shown in
FIG. 52, the wearable display unit 220a of the present embodiment further
comprises: a projection length adjustment part 260 for adjusting the
projection length of the auxiliary holding part 240a; a distance
adjustment part 265 for adjusting the distance from the attachment 227 to
the holding part 221; a joint 270 for fixing the holding part 221
swingably to the attachment 227; and a spring coil 275 as a pressing
force generation means that generates a pressing force F at the auxiliary
holding part 240a.

[0319]On the side of the image display unit 222 of the display support
member housing part 225 of the holding part 221, is provided a fixing
part for fixing the auxiliary holding part 240a. A shaft portion of the
auxiliary holding part 240a of the present embodiment is formed with a
male screw 261. The fixing part of the display support member housing
part 225 is formed with a female screw 262 into which the male screw 261
of the auxiliary holding part 240a is screwed and coupled. The projection
length adjustment part 260 comprises the male screw 261 formed in the
shaft portion of the auxiliary holding part 240a and the female screw 262
formed in the fixing part of the display support member housing part 225.
Thus, the auxiliary holding part 240a can change its projection length in
relation to the display support member housing part 225 by rotating its
shaft portion.

[0320]As shown in FIGS. 52 and 53, the attachment 227 is formed with a
projection 227a that projects toward the holding part 221. The distance
adjustment part 265 comprises: a coupling recess 265b that is coupled
with the projection 227a of the attachment 227; and a projection 265a
that is similar in shape to the projection 227a of the attachment 227. As
shown in FIG. 54, by determining whether the distance adjustment part 265
is used or not, or one or more distance adjustment parts 265 should be
used, or in other words, by changing the number of the distance
adjustment part 265 used in layers, it is possible to adjust the distance
from the attachment 227 to the holding part 221 at a connection part
connecting the attachment 227 and the holding part 221.

[0321]As shown in FIGS. 52 and 53, the joint 270 comprises: a bearing
member 271 that is coupled with the projection 227a of the attachment or
the projection 265a of the distance adjustment part 265; and a shaft
member 272 that can be rotated in relation to the bearing member 271. One
end of the shaft member 272 is rotatably received in the bearing member
271, and the other end is fixed to the display support member housing
part 225. Further, the shaft member 272 is arranged to become almost
parallel with the vertical direction when the wearable display system of
the present embodiment is mounted on the head H. As a result, owing to
this joint 270, the holding part 221 can swing in the direction of
Vθ with respect to the attachment 227 within a horizontal plane in
a state where the wearable display system of the present embodiment is
mounted on the head H, or in other words within a plane that includes the
attachment 227 and the direction of action of the pressing force F of the
auxiliary holding part 240a.

[0322]As shown in FIG. 52, the spring coil 275 is placed on the side of
the image display unit, in relation to the shaft member 272 of the joint
270. One end of the spring coil 275 is fixed to the bearing member 271 of
the joint 270, and the other end is fixed to the inside wall surface on
the outer side of the display support member housing part 225. The coil
spring 275 is arranged in a stretched state, and thus biases the holding
part 221 as well as the auxiliary holding part 240a provided on the
holding part 221 toward the head H. As a result, owing to the spring 275,
the auxiliary holding part 240a maintains the pressing force F of certain
strength against the head H.

[0323]As described above, according to the present embodiment, it is
possible to incline the holding part 221 within the plane that includes
the direction of action of the pressing force F of the auxiliary holding
part 240a, i.e. a horizontal plane at the time of using the wearable
display unit, by changing the number of the distance adjustment parts 265
and/or by rotating the auxiliary holding part 240a. Thus, it is possible
to adjust the position of the image display unit 222 in the horizontal
direction in relation to the head H. In particular, by providing the
projection length adjustment part 260, it is possible to make fine
adjustment of the horizontal position of the image display unit 222 in
relation to the head H, even when the wearable display unit is mounted on
the head H and the pressing force F of the auxiliary holding part 240a is
acting.

[0324]The present embodiment is provided with both the distance adjustment
part 265 and the projection length adjustment part 260 in order to
incline the holding part 221 within the plane including the direction of
action of the pressing force F of the auxiliary holding part 240a.
However, only one of these parts 265 and 260 may be used. Here, it is
necessary to prepare the distance adjustment part(s) 265 in advance
before using the wearable display unit. On the other hand, the projection
length adjustment part 260 can change the inclination of the holding part
221 both before and in course of using the wearable display unit. Thus,
in the case where one of these parts 265 and 260 is employed, it is
favorable in the present embodiment to provide only the projection length
adjustment part 260, i.e. one that can change the inclination of the
holding part 221 even when the wearable display unit is in use.

[0325]Further, the projection length adjustment part 260 of the present
embodiment employs the screw mechanism to adjust the projection length of
the auxiliary holding part 240a. However, for example a cam mechanism or
a mechanism using an electromagnet may be employed as far as the
projection length of the auxiliary holding part 240 can be adjusted.
Further, the present embodiment employs the coil spring 275 as a pressing
force generation means. Of course, instead of the coil spring 275,
another elastic member, an electromagnet, or the like may be used.
Further, the present embodiment employs the distance adjustment part 265
as a distance adjustment means. Instead, a screw mechanism may be
employed similarly to the case of the projection length adjustment part.

[0326]As described above, according to the seventh through tenth
embodiments, it is possible to provide a wearable display unit that has
improved visibility of surroundings. In particular, by providing the
auxiliary holding part on the holding part, it is possible to improve the
wearable display unit in its visibility of surroundings, since the
auxiliary holding part scarcely enters the field of vision of the user.

[0327]In the seventh through tenth embodiments, the wearable display unit
is fixed to the left side of the headphones. However, the wearable
display unit may be fixed either left or right side of the head, and it
may be arranged that the control unit can suitably switch the display
image.

[0328]Further, it is not necessary to provide the power source in the
outside. For example, a battery may be provided in the display support
member housing part. Further, it may be arranged that sound/picture
signals are received wirelessly.

Eleventh Embodiment

[0329]An eleventh embodiment of a wearable display system of which the
image display unit can be arranged near a user's eye will be described
referring to FIGS. 55-58.

[0330]FIG. 55 is a perspective view showing a state that the wearable
display unit of the present embodiment is mounted on the head; and FIG.
56 is a cutaway plan view showing main parts of the wearable display unit
in the mounted state.

[0331]The wearable display unit of the present embodiment comprises: an
image display unit 310 for displaying an image in front of a user's eye;
a head mounting belt 330 that is mounted on a head of a user; an
attachment 340 fixed to the head mounting belt 330; a holding part 320
whose one end is fixed to the image display unit 310 while the other end
extends up to a position opposed to the attachment 340; and joint parts
351 and 355 for fixing the holding part 320 swingably to the attachment
340.

[0332]In the present embodiment, the head mounting belt 330 is headphones,
and comprises: a pair of left and right speakers 331R and 331L; and a
headphone arm 332 that connects the left and right speakers 331R and 331L
with each other. Further, the holding part 320 comprises: a display
support member 321 whose one end is fixed to the image display unit 310;
and a display support member housing part 322 for housing the display
support member 321. The display support member housing part 322 holds the
display support member 321 such that the display support member 321 can
be displaced between a housed state in which the display support member
321 is almost housed and a using state in which the image display unit
310 fixed at the end of the display support member 321 can be positioned
in front of a user's eye.

[0334]Similarly to the first embodiment, the attachment 340 is made of
elastic material such as resin and is formed to have a C-shaped cross
section to grasp the headphone arm 332.

[0335]Here, for the sake of convenience of description in the following,
an axis in which the headphone arm 332 extends at the position where the
attachment 340 is mounted is referred to as the Z-axis; an axis
perpendicular to the Z-axis, extending in the direction from the
attachment 340 toward the side where the display support member housing
part 322 is provided, is referred to as the H-axis; and an axis
perpendicular both to the Z-axis and H-axis is referred to as the V-axis.
Further, the direction around the Z-axis is referred to as Zθ, the
direction around the H-axis as Hθ, and the direction around the
V-axis as Vθ.

[0336]As shown in FIGS. 56 and 57, the attachment 340 comprises: a first
joint part 351 that indirectly supports the holding part 320 such that
the holding part 320 can swing in relation to the attachment 340 in the
Hθ direction; and a second joint part 355 that indirectly supports
the holding part 320 such that the holding part 320 can swing in relation
to the attachment 340 in the Vθ direction.

[0337]The first joint part 351 comprises: a shaft member 352 that extends
from the attachment 340 in the direction parallel with the H-axis; a
bearing member 353a that support the shaft member 352 in a relatively
rotatable manner around the H-axis. Further, the second joint part 355
comprises: a shaft member 356 that extends in the direction parallel with
the V-axis within the display support member housing part 322 of the
holding part 320; and a bearing member 353b that supports the shaft
member 356 in a relatively rotatable manner around the V-axis. The
bearing member 353a of the first joint part 351 and the bearing member
353b of the second joint part 355 are the same bearing member 353. The
torque required for the bearing member 353a to rotate around the H-axis
relatively to the shaft member 352 of the first joint part 351 is larger
than the torque required for the bearing member 353b to rotate around the
V-axis relatively to the shaft member 356 of the second joint part 353.
Namely, as shown in FIG. 55, the torque required for the image display
unit 310 to swing around the H-axis in the direction including vertical
direction is larger than the torque required for the image display unit
310 to swing around the V-axis in the direction including horizontal
direction. Thus, the torque around the H-axis is determined such that the
image display unit 310 does not easily move down by rotating around the
H-axis owing to its own weight or owing to vertical movement of the head.
On the other hand, the swinging torque required for the image display
unit 310 to swing around the V-axis in the direction including the
horizontal direction is determined such that the image display unit 310
does not easily rotate around the V-axis only owing to swing of the head
in the horizontal direction. In the present embodiment, to differentiate
the torque in the joint part 351 and the torque in the joint part 355,
materials of the sliding parts of each joint part are selected such that
the coefficient of friction between the shaft member 352 and the bearing
member 353a of the first joint part 351 is different from the coefficient
of friction between the shaft member 356 and the bearing member 353b of
the second joint part.

[0338]As described above, in the present embodiment, the torque required
for swinging the holding part 320 around the H-axis is relatively large.
As a result, after the vertical position of the image display unit 310
fixed to the holding part 320 is once adjusted, the image display unit
310 does not happen to move relatively to the head owing to the weight of
the image display unit 310 itself or owing to swinging of the head.
Further, the torque required for swinging the holding part 320 around the
V-axis is relatively small, and thus the horizontal position of the image
display unit 310 fixed to the holding part 320 can be easily adjusted.
Further, in the present embodiment, the attachment 340 can be rotated in
relation to the headphone arm 332 around the Z-axis, it is possible to
adjust the position of the image display unit 310 around the Z-axis, i.e.
to adjust the inclination of the screen of the image display unit 310.

[0339]Further, in the present embodiment, multiple joint parts are
gathered at the end portion of the holding part 320. Thus, simple
operation can move the image display unit 310 in various directions. For
example, if a first joint part for moving the image display unit 310
vertically were provided between the holding part 320 and the attachment
340 and a second joint part for moving the image display unit 310
horizontally were provided in the mid portion of the holding part 320,
then one joint part might be fixed not to move in the course of operating
the other joint part. On the other hand, in the present embodiment,
operation of fixing one of a plurality of joint parts is not necessary
when the image display unit 310 is moved, similarly to a joint part
having a spherical seat that enables movement in various directions as
shown in the technique described in Patent Document 3 mentioned as the
background technique above.

[0340]As in the above embodiment, as a method of making the torque of one
joint part 351 larger than the torque of the other joint part 355 among a
plurality of joint parts 351, 355, there is a method of selecting
materials of shaft members 351, 356 and bearing members 353. As another
method, may be mentioned a method of interposing a torque adjustment
member 357 such as an O-ring as shown in FIG. 58, or a method of forming
a plurality of notches in one of a shaft member 51 and a bearing member
53 to change the coefficient of friction.

[0341]Further, in the above embodiment, as the first joint part 351, a
shaft member 352 is formed in the attachment 340. However, the attachment
340 may be formed with a bearing member. Further, as the second joint
part 355, the shaft member 356 is fixed to the display support member
holding part 322 of the holding part 320. However, a bearing member may
be provided in the display support member holding part 322. In that case,
a member common to the first and second joint parts becomes a shaft
member that couples both into the bearing member of the first joint part
and into the bearing member of the second joint part.

[0342]Further, in the above embodiment, the attachment can be coupled to
and removed from the headphone arm 322 of the head mounting belt 330.
However, an attachment that can not be removed from the headphone arm 332
may be used.

[0343]Further, of course, the displacement mechanism having a plurality of
joint parts 351, 355, which is described in the present embodiment, may
be applied to the first through tenth embodiments and the variants of
those embodiments, giving the similar effects.